diff --git a/docs/changes/1.2.0.md b/docs/changes/1.2.0.md
index 4247f38b8..3be80952c 100644
--- a/docs/changes/1.2.0.md
+++ b/docs/changes/1.2.0.md
@@ -30,6 +30,7 @@
 - ODPresentation Reader : Read differents units for margin by [@Progi1984](https://github.com/Progi1984) fixing [#830](https://github.com/PHPOffice/PHPPresentation/pull/830) in [#847](https://github.com/PHPOffice/PHPPresentation/pull/847)
 - PowerPoint2007 Reader : Fixed loading of fonts by [@ag3202](https://github.com/ag3202) and [@Progi1984](https://github.com/Progi1984) in [#851](https://github.com/PHPOffice/PHPPresentation/pull/851)
 - PhpOffice\PhpPresentation\Style\TextStyle : Fixed typo for default indent by [@Progi1984](https://github.com/Progi1984) in [#857](https://github.com/PHPOffice/PHPPresentation/pull/857)
+- Fixed adding custom SVGs by [@seanlynchwv](http://github.com/seanlynchwv) in [#881](https://github.com/PHPOffice/PHPPresentation/pull/881)
 
 ## Miscellaneous
 - CI: Added ODFValidator by [@Progi1984](https://github.com/Progi1984) fixing [#678](https://github.com/PHPOffice/PHPWord/issues/678) in [#653](https://github.com/PHPOffice/PHPWord/pull/653)
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;