diff --git a/docs/changes/1.3.0.md b/docs/changes/1.3.0.md
index 33b870b7a..cbf2bd7de 100644
--- a/docs/changes/1.3.0.md
+++ b/docs/changes/1.3.0.md
@@ -6,4 +6,5 @@
 - `phpoffice/phpspreadsheet`: Allow version 5.0 by [@seanlynchwv](http://github.com/seanlynchwv) in [#879](https://github.com/PHPOffice/PHPPresentation/pull/879)
 
 ## Bug fixes
+- Fixed adding custom SVGs by [@seanlynchwv](http://github.com/seanlynchwv) in [#881](https://github.com/PHPOffice/PHPPresentation/pull/881)
 
diff --git a/src/PhpPresentation/Writer/PowerPoint2007/ContentTypes.php b/src/PhpPresentation/Writer/PowerPoint2007/ContentTypes.php
index 87e4d5b57..0a89c37cc 100644
--- a/src/PhpPresentation/Writer/PowerPoint2007/ContentTypes.php
+++ b/src/PhpPresentation/Writer/PowerPoint2007/ContentTypes.php
@@ -49,8 +49,7 @@ public function render(): ZipInterface
         // XML
         $this->writeDefaultContentType($objWriter, 'xml', 'application/xml');
 
-        // SVG
-        $this->writeDefaultContentType($objWriter, 'svg', 'image/svg+xml');
+        // SVG will pre-register in $aMediaContentTypes
 
         // Presentation
         $this->writeOverrideContentType($objWriter, '/ppt/presentation.xml', 'application/vnd.openxmlformats-officedocument.presentationml.presentation.main+xml');
@@ -106,11 +105,12 @@ public function render(): ZipInterface
         // Add media content-types
         $aMediaContentTypes = [];
 
-        // GIF, JPEG, PNG
+        // GIF, JPEG, PNG, SVG
         $aMediaContentTypes['gif'] = 'image/gif';
         $aMediaContentTypes['jpg'] = 'image/jpeg';
         $aMediaContentTypes['jpeg'] = 'image/jpeg';
         $aMediaContentTypes['png'] = 'image/png';
+        $aMediaContentTypes['svg'] = 'image/svg+xml';
         foreach ($aMediaContentTypes as $key => $value) {
             $this->writeDefaultContentType($objWriter, $key, $value);
         }
@@ -133,6 +133,11 @@ public function render(): ZipInterface
                 $extension = strtolower($shapeIndex->getExtension());
                 $mimeType = $shapeIndex->getMimeType();
 
+                // Normalize any odd returns (some environments report "image/svg")
+                if ($extension === 'svg') {
+                    $mimeType = 'image/svg+xml';
+                }
+
                 if (!isset($aMediaContentTypes[$extension])) {
                     $aMediaContentTypes[$extension] = $mimeType;
 
diff --git a/tests/PhpPresentation/Tests/Writer/PowerPoint2007/ContentTypesTest.php b/tests/PhpPresentation/Tests/Writer/PowerPoint2007/ContentTypesTest.php
new file mode 100644
index 000000000..0576bf2a0
--- /dev/null
+++ b/tests/PhpPresentation/Tests/Writer/PowerPoint2007/ContentTypesTest.php
@@ -0,0 +1,48 @@
+<?php
+
+declare(strict_types=1);
+
+namespace PhpPresentation\Tests\Writer\PowerPoint2007;
+
+use PhpOffice\PhpPresentation\PhpPresentation;
+use PhpOffice\PhpPresentation\IOFactory;
+use PHPUnit\Framework\TestCase;
+
+class ContentTypesTest extends TestCase
+{
+    public function testSvgDefaultContentTypeIsWritten(): void
+    {
+        $presentation = new PhpPresentation();
+
+        $pptxFile = tempnam(sys_get_temp_dir(), 'pptx_svg_test_');
+        $writer = IOFactory::createWriter($presentation, 'PowerPoint2007');
+        $writer->save($pptxFile);
+
+        $zip = new \ZipArchive();
+        $this->assertTrue(
+            $zip->open($pptxFile),
+            'Could not open generated PPTX as ZipArchive'
+        );
+
+        $contentTypesXml = $zip->getFromName('[Content_Types].xml');
+        $zip->close();
+        @unlink($pptxFile);
+
+        $this->assertIsString(
+            $contentTypesXml,
+            '[Content_Types].xml not found in archive'
+        );
+
+        $this->assertStringContainsString(
+            'Extension="svg"',
+            $contentTypesXml,
+            'SVG extension not registered in [Content_Types].xml'
+        );
+
+        $this->assertStringContainsString(
+            'image/svg+xml',
+            $contentTypesXml,
+            'SVG MIME type not registered correctly in [Content_Types].xml'
+        );
+    }
+}