diff --git a/samples/images/bmp.bmp b/samples/images/bmp.bmp
new file mode 100644
index 00000000..01fee85e
Binary files /dev/null and b/samples/images/bmp.bmp differ
diff --git a/samples/images/gif.gif b/samples/images/gif.gif
new file mode 100644
index 00000000..4cf06035
Binary files /dev/null and b/samples/images/gif.gif differ
diff --git a/src/PhpSpreadsheet/Shared/OLE.php b/src/PhpSpreadsheet/Shared/OLE.php
index 32b56e18..25d698a5 100644
--- a/src/PhpSpreadsheet/Shared/OLE.php
+++ b/src/PhpSpreadsheet/Shared/OLE.php
@@ -505,7 +505,7 @@ class OLE
         // days from 1-1-1601 until the beggining of UNIX era
         $days = 134774;
         // calculate seconds
-        $big_date = $days * 24 * 3600 + gmmktime(date('H', $date), date('i', $date), date('s', $date), date('m', $date), date('d', $date), date('Y', $date));
+        $big_date = $days * 24 * 3600 + mktime((int) date('H', $date), (int) date('i', $date), (int) date('s', $date), (int) date('m', $date), (int) date('d', $date), (int) date('Y', $date));
         // multiply just to make MS happy
         $big_date *= 10000000;
 
@@ -558,10 +558,9 @@ class OLE
         // translate to seconds since 1970:
         $unixTimestamp = floor(65536.0 * 65536.0 * $timestampHigh + $timestampLow - $days * 24 * 3600 + 0.5);
 
-        if ((int) $unixTimestamp == $unixTimestamp) {
-            return (int) $unixTimestamp;
-        }
+        $iTimestamp = (int) $unixTimestamp;
 
-        return $unixTimestamp >= 0.0 ? PHP_INT_MAX : PHP_INT_MIN;
+        // Overflow conditions can't happen on 64-bit system
+        return ($iTimestamp == $unixTimestamp) ? $iTimestamp : ($unixTimestamp >= 0.0 ? PHP_INT_MAX : PHP_INT_MIN);
     }
 }
diff --git a/src/PhpSpreadsheet/Writer/Xls.php b/src/PhpSpreadsheet/Writer/Xls.php
index cf87d5be..4f4b256a 100644
--- a/src/PhpSpreadsheet/Writer/Xls.php
+++ b/src/PhpSpreadsheet/Writer/Xls.php
@@ -23,7 +23,6 @@ use PhpOffice\PhpSpreadsheet\Spreadsheet;
 use PhpOffice\PhpSpreadsheet\Worksheet\BaseDrawing;
 use PhpOffice\PhpSpreadsheet\Worksheet\Drawing;
 use PhpOffice\PhpSpreadsheet\Worksheet\MemoryDrawing;
-use RuntimeException;
 
 class Xls extends BaseWriter
 {
@@ -389,13 +388,94 @@ class Xls extends BaseWriter
         }
     }
 
-    /**
-     * Build the Escher object corresponding to the MSODRAWINGGROUP record.
-     */
-    private function buildWorkbookEscher(): void
+    private function processMemoryDrawing(BstoreContainer &$bstoreContainer, BaseDrawing $drawing, string $renderingFunctionx): void
     {
-        $escher = null;
+        switch ($renderingFunctionx) {
+            case MemoryDrawing::RENDERING_JPEG:
+                $blipType = BSE::BLIPTYPE_JPEG;
+                $renderingFunction = 'imagejpeg';
 
+                break;
+            default:
+                $blipType = BSE::BLIPTYPE_PNG;
+                $renderingFunction = 'imagepng';
+
+                break;
+        }
+
+        ob_start();
+        call_user_func($renderingFunction, $drawing->getImageResource());
+        $blipData = ob_get_contents();
+        ob_end_clean();
+
+        $blip = new Blip();
+        $blip->setData($blipData);
+
+        $BSE = new BSE();
+        $BSE->setBlipType($blipType);
+        $BSE->setBlip($blip);
+
+        $bstoreContainer->addBSE($BSE);
+    }
+
+    private function processDrawing(BstoreContainer &$bstoreContainer, BaseDrawing $drawing): void
+    {
+        $blipData = '';
+        $filename = $drawing->getPath();
+
+        [$imagesx, $imagesy, $imageFormat] = getimagesize($filename);
+
+        switch ($imageFormat) {
+            case 1: // GIF, not supported by BIFF8, we convert to PNG
+                $blipType = BSE::BLIPTYPE_PNG;
+                ob_start();
+                imagepng(imagecreatefromgif($filename));
+                $blipData = ob_get_contents();
+                ob_end_clean();
+
+                break;
+            case 2: // JPEG
+                $blipType = BSE::BLIPTYPE_JPEG;
+                $blipData = file_get_contents($filename);
+
+                break;
+            case 3: // PNG
+                $blipType = BSE::BLIPTYPE_PNG;
+                $blipData = file_get_contents($filename);
+
+                break;
+            case 6: // Windows DIB (BMP), we convert to PNG
+                $blipType = BSE::BLIPTYPE_PNG;
+                ob_start();
+                imagepng(SharedDrawing::imagecreatefrombmp($filename));
+                $blipData = ob_get_contents();
+                ob_end_clean();
+
+                break;
+        }
+        if ($blipData) {
+            $blip = new Blip();
+            $blip->setData($blipData);
+
+            $BSE = new BSE();
+            $BSE->setBlipType($blipType);
+            $BSE->setBlip($blip);
+
+            $bstoreContainer->addBSE($BSE);
+        }
+    }
+
+    private function processBaseDrawing(BstoreContainer &$bstoreContainer, BaseDrawing $drawing): void
+    {
+        if ($drawing instanceof Drawing) {
+            $this->processDrawing($bstoreContainer, $drawing);
+        } elseif ($drawing instanceof MemoryDrawing) {
+            $this->processMemoryDrawing($bstoreContainer, $drawing, $drawing->getRenderingFunction());
+        }
+    }
+
+    private function checkForDrawings(): bool
+    {
         // any drawings in this workbook?
         $found = false;
         foreach ($this->spreadsheet->getAllSheets() as $sheet) {
@@ -406,8 +486,16 @@ class Xls extends BaseWriter
             }
         }
 
+        return $found;
+    }
+
+    /**
+     * Build the Escher object corresponding to the MSODRAWINGGROUP record.
+     */
+    private function buildWorkbookEscher(): void
+    {
         // nothing to do if there are no drawings
-        if (!$found) {
+        if (!$this->checkForDrawings()) {
             return;
         }
 
@@ -429,17 +517,16 @@ class Xls extends BaseWriter
         foreach ($this->spreadsheet->getAllsheets() as $sheet) {
             $sheetCountShapes = 0; // count number of shapes (minus group shape), in sheet
 
-            if (count($sheet->getDrawingCollection()) > 0) {
-                ++$countDrawings;
+            $addCount = 0;
+            foreach ($sheet->getDrawingCollection() as $drawing) {
+                $addCount = 1;
+                ++$sheetCountShapes;
+                ++$totalCountShapes;
 
-                foreach ($sheet->getDrawingCollection() as $drawing) {
-                    ++$sheetCountShapes;
-                    ++$totalCountShapes;
-
-                    $spId = $sheetCountShapes | ($this->spreadsheet->getIndex($sheet) + 1) << 10;
-                    $spIdMax = max($spId, $spIdMax);
-                }
+                $spId = $sheetCountShapes | ($this->spreadsheet->getIndex($sheet) + 1) << 10;
+                $spIdMax = max($spId, $spIdMax);
             }
+            $countDrawings += $addCount;
         }
 
         $dggContainer->setSpIdMax($spIdMax + 1);
@@ -453,83 +540,7 @@ class Xls extends BaseWriter
         // the BSE's (all the images)
         foreach ($this->spreadsheet->getAllsheets() as $sheet) {
             foreach ($sheet->getDrawingCollection() as $drawing) {
-                if (!extension_loaded('gd')) {
-                    throw new RuntimeException('Saving images in xls requires gd extension');
-                }
-                if ($drawing instanceof Drawing) {
-                    $filename = $drawing->getPath();
-
-                    [$imagesx, $imagesy, $imageFormat] = getimagesize($filename);
-
-                    switch ($imageFormat) {
-                        case 1: // GIF, not supported by BIFF8, we convert to PNG
-                            $blipType = BSE::BLIPTYPE_PNG;
-                            ob_start();
-                            imagepng(imagecreatefromgif($filename));
-                            $blipData = ob_get_contents();
-                            ob_end_clean();
-
-                            break;
-                        case 2: // JPEG
-                            $blipType = BSE::BLIPTYPE_JPEG;
-                            $blipData = file_get_contents($filename);
-
-                            break;
-                        case 3: // PNG
-                            $blipType = BSE::BLIPTYPE_PNG;
-                            $blipData = file_get_contents($filename);
-
-                            break;
-                        case 6: // Windows DIB (BMP), we convert to PNG
-                            $blipType = BSE::BLIPTYPE_PNG;
-                            ob_start();
-                            imagepng(SharedDrawing::imagecreatefrombmp($filename));
-                            $blipData = ob_get_contents();
-                            ob_end_clean();
-
-                            break;
-                        default:
-                            continue 2;
-                    }
-
-                    $blip = new Blip();
-                    $blip->setData($blipData);
-
-                    $BSE = new BSE();
-                    $BSE->setBlipType($blipType);
-                    $BSE->setBlip($blip);
-
-                    $bstoreContainer->addBSE($BSE);
-                } elseif ($drawing instanceof MemoryDrawing) {
-                    switch ($drawing->getRenderingFunction()) {
-                        case MemoryDrawing::RENDERING_JPEG:
-                            $blipType = BSE::BLIPTYPE_JPEG;
-                            $renderingFunction = 'imagejpeg';
-
-                            break;
-                        case MemoryDrawing::RENDERING_GIF:
-                        case MemoryDrawing::RENDERING_PNG:
-                        case MemoryDrawing::RENDERING_DEFAULT:
-                            $blipType = BSE::BLIPTYPE_PNG;
-                            $renderingFunction = 'imagepng';
-
-                            break;
-                    }
-
-                    ob_start();
-                    call_user_func($renderingFunction, $drawing->getImageResource());
-                    $blipData = ob_get_contents();
-                    ob_end_clean();
-
-                    $blip = new Blip();
-                    $blip->setData($blipData);
-
-                    $BSE = new BSE();
-                    $BSE->setBlipType($blipType);
-                    $BSE->setBlip($blip);
-
-                    $bstoreContainer->addBSE($BSE);
-                }
+                $this->processBaseDrawing($bstoreContainer, $drawing);
             }
         }
 
@@ -578,8 +589,8 @@ class Xls extends BaseWriter
         ++$dataSection_NumProps;
 
         // GKPIDDSI_CATEGORY : Category
-        if ($this->spreadsheet->getProperties()->getCategory()) {
-            $dataProp = $this->spreadsheet->getProperties()->getCategory();
+        $dataProp = $this->spreadsheet->getProperties()->getCategory();
+        if ($dataProp) {
             $dataSection[] = [
                 'summary' => ['pack' => 'V', 'data' => 0x02],
                 'offset' => ['pack' => 'V'],
@@ -707,11 +718,7 @@ class Xls extends BaseWriter
 
                 $dataSection_Content_Offset += 4 + 4;
             } elseif ($dataProp['type']['data'] == 0x0B) { // Boolean
-                if ($dataProp['data']['data'] == false) {
-                    $dataSection_Content .= pack('V', 0x0000);
-                } else {
-                    $dataSection_Content .= pack('V', 0x0001);
-                }
+                $dataSection_Content .= pack('V', (int) $dataProp['data']['data']);
                 $dataSection_Content_Offset += 4 + 4;
             } elseif ($dataProp['type']['data'] == 0x1E) { // null-terminated string prepended by dword string length
                 // Null-terminated string
@@ -725,12 +732,12 @@ class Xls extends BaseWriter
                 $dataSection_Content .= $dataProp['data']['data'];
 
                 $dataSection_Content_Offset += 4 + 4 + strlen($dataProp['data']['data']);
-            } elseif ($dataProp['type']['data'] == 0x40) { // Filetime (64-bit value representing the number of 100-nanosecond intervals since January 1, 1601)
-                $dataSection_Content .= $dataProp['data']['data'];
+            // Condition below can never be true
+            //} elseif ($dataProp['type']['data'] == 0x40) { // Filetime (64-bit value representing the number of 100-nanosecond intervals since January 1, 1601)
+            //    $dataSection_Content .= $dataProp['data']['data'];
 
-                $dataSection_Content_Offset += 4 + 8;
+            //    $dataSection_Content_Offset += 4 + 8;
             } else {
-                // Data Type Not Used at the moment
                 $dataSection_Content .= $dataProp['data']['data'];
 
                 $dataSection_Content_Offset += 4 + $dataProp['data']['length'];
@@ -752,6 +759,32 @@ class Xls extends BaseWriter
         return $data;
     }
 
+    private function writeSummaryPropOle(int $dataProp, int &$dataSection_NumProps, array &$dataSection, int $sumdata, int $typdata): void
+    {
+        if ($dataProp) {
+            $dataSection[] = [
+                'summary' => ['pack' => 'V', 'data' => $sumdata],
+                'offset' => ['pack' => 'V'],
+                'type' => ['pack' => 'V', 'data' => $typdata], // null-terminated string prepended by dword string length
+                'data' => ['data' => OLE::localDateToOLE($dataProp)],
+            ];
+            ++$dataSection_NumProps;
+        }
+    }
+
+    private function writeSummaryProp(string $dataProp, int &$dataSection_NumProps, array &$dataSection, int $sumdata, int $typdata): void
+    {
+        if ($dataProp) {
+            $dataSection[] = [
+                'summary' => ['pack' => 'V', 'data' => $sumdata],
+                'offset' => ['pack' => 'V'],
+                'type' => ['pack' => 'V', 'data' => $typdata], // null-terminated string prepended by dword string length
+                'data' => ['data' => $dataProp, 'length' => strlen($dataProp)],
+            ];
+            ++$dataSection_NumProps;
+        }
+    }
+
     /**
      * Build the OLE Part for Summary Information.
      *
@@ -792,94 +825,16 @@ class Xls extends BaseWriter
         ];
         ++$dataSection_NumProps;
 
-        //    Title
-        if ($this->spreadsheet->getProperties()->getTitle()) {
-            $dataProp = $this->spreadsheet->getProperties()->getTitle();
-            $dataSection[] = [
-                'summary' => ['pack' => 'V', 'data' => 0x02],
-                'offset' => ['pack' => 'V'],
-                'type' => ['pack' => 'V', 'data' => 0x1E], // null-terminated string prepended by dword string length
-                'data' => ['data' => $dataProp, 'length' => strlen($dataProp)],
-            ];
-            ++$dataSection_NumProps;
-        }
-        //    Subject
-        if ($this->spreadsheet->getProperties()->getSubject()) {
-            $dataProp = $this->spreadsheet->getProperties()->getSubject();
-            $dataSection[] = [
-                'summary' => ['pack' => 'V', 'data' => 0x03],
-                'offset' => ['pack' => 'V'],
-                'type' => ['pack' => 'V', 'data' => 0x1E], // null-terminated string prepended by dword string length
-                'data' => ['data' => $dataProp, 'length' => strlen($dataProp)],
-            ];
-            ++$dataSection_NumProps;
-        }
-        //    Author (Creator)
-        if ($this->spreadsheet->getProperties()->getCreator()) {
-            $dataProp = $this->spreadsheet->getProperties()->getCreator();
-            $dataSection[] = [
-                'summary' => ['pack' => 'V', 'data' => 0x04],
-                'offset' => ['pack' => 'V'],
-                'type' => ['pack' => 'V', 'data' => 0x1E], // null-terminated string prepended by dword string length
-                'data' => ['data' => $dataProp, 'length' => strlen($dataProp)],
-            ];
-            ++$dataSection_NumProps;
-        }
-        //    Keywords
-        if ($this->spreadsheet->getProperties()->getKeywords()) {
-            $dataProp = $this->spreadsheet->getProperties()->getKeywords();
-            $dataSection[] = [
-                'summary' => ['pack' => 'V', 'data' => 0x05],
-                'offset' => ['pack' => 'V'],
-                'type' => ['pack' => 'V', 'data' => 0x1E], // null-terminated string prepended by dword string length
-                'data' => ['data' => $dataProp, 'length' => strlen($dataProp)],
-            ];
-            ++$dataSection_NumProps;
-        }
-        //    Comments (Description)
-        if ($this->spreadsheet->getProperties()->getDescription()) {
-            $dataProp = $this->spreadsheet->getProperties()->getDescription();
-            $dataSection[] = [
-                'summary' => ['pack' => 'V', 'data' => 0x06],
-                'offset' => ['pack' => 'V'],
-                'type' => ['pack' => 'V', 'data' => 0x1E], // null-terminated string prepended by dword string length
-                'data' => ['data' => $dataProp, 'length' => strlen($dataProp)],
-            ];
-            ++$dataSection_NumProps;
-        }
-        //    Last Saved By (LastModifiedBy)
-        if ($this->spreadsheet->getProperties()->getLastModifiedBy()) {
-            $dataProp = $this->spreadsheet->getProperties()->getLastModifiedBy();
-            $dataSection[] = [
-                'summary' => ['pack' => 'V', 'data' => 0x08],
-                'offset' => ['pack' => 'V'],
-                'type' => ['pack' => 'V', 'data' => 0x1E], // null-terminated string prepended by dword string length
-                'data' => ['data' => $dataProp, 'length' => strlen($dataProp)],
-            ];
-            ++$dataSection_NumProps;
-        }
-        //    Created Date/Time
-        if ($this->spreadsheet->getProperties()->getCreated()) {
-            $dataProp = $this->spreadsheet->getProperties()->getCreated();
-            $dataSection[] = [
-                'summary' => ['pack' => 'V', 'data' => 0x0C],
-                'offset' => ['pack' => 'V'],
-                'type' => ['pack' => 'V', 'data' => 0x40], // Filetime (64-bit value representing the number of 100-nanosecond intervals since January 1, 1601)
-                'data' => ['data' => OLE::localDateToOLE($dataProp)],
-            ];
-            ++$dataSection_NumProps;
-        }
-        //    Modified Date/Time
-        if ($this->spreadsheet->getProperties()->getModified()) {
-            $dataProp = $this->spreadsheet->getProperties()->getModified();
-            $dataSection[] = [
-                'summary' => ['pack' => 'V', 'data' => 0x0D],
-                'offset' => ['pack' => 'V'],
-                'type' => ['pack' => 'V', 'data' => 0x40], // Filetime (64-bit value representing the number of 100-nanosecond intervals since January 1, 1601)
-                'data' => ['data' => OLE::localDateToOLE($dataProp)],
-            ];
-            ++$dataSection_NumProps;
-        }
+        $props = $this->spreadsheet->getProperties();
+        $this->writeSummaryProp($props->getTitle(), $dataSection_NumProps, $dataSection, 0x02, 0x1e);
+        $this->writeSummaryProp($props->getSubject(), $dataSection_NumProps, $dataSection, 0x03, 0x1e);
+        $this->writeSummaryProp($props->getCreator(), $dataSection_NumProps, $dataSection, 0x04, 0x1e);
+        $this->writeSummaryProp($props->getKeywords(), $dataSection_NumProps, $dataSection, 0x05, 0x1e);
+        $this->writeSummaryProp($props->getDescription(), $dataSection_NumProps, $dataSection, 0x06, 0x1e);
+        $this->writeSummaryProp($props->getLastModifiedBy(), $dataSection_NumProps, $dataSection, 0x08, 0x1e);
+        $this->writeSummaryPropOle($props->getCreated(), $dataSection_NumProps, $dataSection, 0x0c, 0x40);
+        $this->writeSummaryPropOle($props->getModified(), $dataSection_NumProps, $dataSection, 0x0d, 0x40);
+
         //    Security
         $dataSection[] = [
             'summary' => ['pack' => 'V', 'data' => 0x13],
diff --git a/tests/PhpSpreadsheetTests/Writer/Xls/XlsGifBmpTest.php b/tests/PhpSpreadsheetTests/Writer/Xls/XlsGifBmpTest.php
new file mode 100644
index 00000000..ceba7e54
--- /dev/null
+++ b/tests/PhpSpreadsheetTests/Writer/Xls/XlsGifBmpTest.php
@@ -0,0 +1,84 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheetTests\Writer\Xls;
+
+use PhpOffice\PhpSpreadsheet\Spreadsheet;
+use PhpOffice\PhpSpreadsheet\Worksheet\Drawing;
+use PhpOffice\PhpSpreadsheet\Worksheet\MemoryDrawing;
+use PhpOffice\PhpSpreadsheetTests\Functional\AbstractFunctional;
+
+class XlsGifBmpTest extends AbstractFunctional
+{
+    private $filename = '';
+
+    protected function tearDown(): void
+    {
+        if ($this->filename) {
+            unlink($this->filename);
+        }
+        $this->filename = '';
+    }
+
+    public function testBmp(): void
+    {
+        $pgmstart = time();
+        $spreadsheet = new Spreadsheet();
+        $filstart = $spreadsheet->getProperties()->getModified();
+        self::assertLessThanOrEqual($filstart, $pgmstart);
+
+        // Add a drawing to the worksheet
+        $drawing = new Drawing();
+        $drawing->setName('Letters B, M, and P');
+        $drawing->setDescription('Handwritten B, M, and P');
+        $drawing->setPath(__DIR__ . '/../../../../samples/images/bmp.bmp');
+        $drawing->setHeight(36);
+        $drawing->setWorksheet($spreadsheet->getActiveSheet());
+        $drawing->setCoordinates('A1');
+
+        $reloadedSpreadsheet = $this->writeAndReload($spreadsheet, 'Xls');
+        $creationDatestamp = $reloadedSpreadsheet->getProperties()->getCreated();
+        $filstart = $creationDatestamp;
+        $pSheet = $reloadedSpreadsheet->getActiveSheet();
+        $drawings = $pSheet->getDrawingCollection();
+        self::assertCount(1, $drawings);
+        foreach ($pSheet->getDrawingCollection() as $drawing) {
+            // See if Scrutinizer approves this
+            $mimeType = ($drawing instanceof MemoryDrawing) ? $drawing->getMimeType() : 'notmemorydrawing';
+            self::assertEquals('image/png', $mimeType);
+        }
+        $pgmend = time();
+
+        self::assertLessThanOrEqual($pgmend, $pgmstart);
+        self::assertLessThanOrEqual($pgmend, $filstart);
+        self::assertLessThanOrEqual($filstart, $pgmstart);
+    }
+
+    public function testGif(): void
+    {
+        $spreadsheet = new Spreadsheet();
+
+        // Add a drawing to the worksheet
+        $drawing = new Drawing();
+        $drawing->setName('Letters G, I, and G');
+        $drawing->setDescription('Handwritten G, I, and F');
+        $drawing->setPath(__DIR__ . '/../../../../samples/images/gif.gif');
+        $drawing->setHeight(36);
+        $drawing->setWorksheet($spreadsheet->getActiveSheet());
+        $drawing->setCoordinates('A1');
+
+        $reloadedSpreadsheet = $this->writeAndReload($spreadsheet, 'Xls');
+        $pSheet = $reloadedSpreadsheet->getActiveSheet();
+        $drawings = $pSheet->getDrawingCollection();
+        self::assertCount(1, $drawings);
+        foreach ($pSheet->getDrawingCollection() as $drawing) {
+            $mimeType = ($drawing instanceof MemoryDrawing) ? $drawing->getMimeType() : 'notmemorydrawing';
+            self::assertEquals('image/png', $mimeType);
+        }
+    }
+
+    public function testInvalidTimestamp(): void
+    {
+        $this->expectException(\PhpOffice\PhpSpreadsheet\Reader\Exception::class);
+        \PhpOffice\PhpSpreadsheet\Shared\OLE::OLE2LocalDate(' ');
+    }
+}