diff --git a/js/components/ascribe_forms/form_register_piece.js b/js/components/ascribe_forms/form_register_piece.js
index 2a0e3fa5..f79e1dca 100644
--- a/js/components/ascribe_forms/form_register_piece.js
+++ b/js/components/ascribe_forms/form_register_piece.js
@@ -87,10 +87,10 @@ let RegisterPieceForm = React.createClass({
         const validFiles = files.filter(displayValidFilesFilter);
 
         if(validFiles.length > 0) {
-            const { type: fileType } = validFiles[0].type;
-            const fileExtension = fileType && fileType.split('/').length ? fileType.split('/')[1]
+            const { type: mimeType } = validFiles[0];
+            const mimeSubType = mimeType && mimeType.split('/').length ? mimeType.split('/')[1]
                                                                          : 'unknown';
-            const thumbnailKeyDialogExpanded = AppConstants.supportedThumbnailFileFormats.indexOf(fileExtension) === -1;
+            const thumbnailKeyDialogExpanded = AppConstants.supportedThumbnailFileFormats.indexOf(mimeSubType) === -1;
             this.setState({ thumbnailKeyDialogExpanded });
         } else {
             this.setState({ thumbnailKeyDialogExpanded: false });
diff --git a/js/constants/application_constants.js b/js/constants/application_constants.js
index 061eb9db..79d00747 100644
--- a/js/constants/application_constants.js
+++ b/js/constants/application_constants.js
@@ -88,7 +88,14 @@ const constants = {
 
     'searchThreshold': 500,
 
-    'supportedThumbnailFileFormats': ['png', 'jpg', 'jpeg', 'gif', 'mp4'],
+    'supportedThumbnailFileFormats': [
+        'x-sgi-movie', 'x-msvideo', 'quicktime', 'mpeg', 'png', 'jpeg', 'gif',
+        'ogg', 'oga', 'ogv', 'ogx', 'wmv', 'wma', 'flv', '3gpp2', '3p2', '3pg',
+        'png', 'jpg', 'jpeg', 'gif', '264', '3g', '3g2', '3gp', '3gp2', '3gpp',
+        'mp4', 'm4a', 'm4v', 'f4v', 'f4a', 'm4b', 'm4r', 'f4b', 'mov', 'quicktime',
+        'webm', 'x264', 'mpeg', 'mpeg4', 'mpg4', 'bmp', 'eps', 'jp2', 'j2k', 'jpm',
+        'mj2'
+    ],
 
     // in case of whitelabel customization, we store stuff here
     'whitelabel': {},