diff --git a/themes/grav/js/mdeditor.js b/themes/grav/js/mdeditor.js
index b10ada41..f207ce2f 100644
--- a/themes/grav/js/mdeditor.js
+++ b/themes/grav/js/mdeditor.js
@@ -149,7 +149,7 @@
             filename = filename.replace(/@3x|@2x|@1x/, '');
             filename = filename.replace(/\(/g, '%28');
             filename = filename.replace(/\)/g, '%29');
-            if (filename.match(/\.(jpg|jpeg|png|gif)$/)) {
+            if (filename.toLowerCase().match(/\.(jpg|jpeg|png|gif)$/)) {
                 editor.doc.replaceSelection('![](' + filename + ')');
             } else {
                 editor.doc.replaceSelection('[' + decodeURI(filename) + '](' + filename + ')');
diff --git a/themes/grav/templates/forms/fields/pagemedia/pagemedia.html.twig b/themes/grav/templates/forms/fields/pagemedia/pagemedia.html.twig
index 4a6e636a..47fd5287 100644
--- a/themes/grav/templates/forms/fields/pagemedia/pagemedia.html.twig
+++ b/themes/grav/templates/forms/fields/pagemedia/pagemedia.html.twig
@@ -80,7 +80,7 @@
                                     thisDropzone.files.push(mockFile);
                                     thisDropzone.options.addedfile.call(thisDropzone, mockFile);
 
-                                    if (filename.match(/\.(jpg|jpeg|png|gif)$/)) {
+                                    if (filename.toLowerCase().match(/\.(jpg|jpeg|png|gif)$/)) {
                                         thisDropzone.options.thumbnail.call(thisDropzone, mockFile, data.url);
                                     }
                                 });