diff --git a/ui/component/publishFile/view.jsx b/ui/component/publishFile/view.jsx
index 0eafc2641..50a47b2c5 100644
--- a/ui/component/publishFile/view.jsx
+++ b/ui/component/publishFile/view.jsx
@@ -242,7 +242,7 @@ function PublishFile(props: Props) {
 
     if (contentType && contentType[0] === 'text') {
       isTextPost = contentType[1] === 'plain' || contentType[1] === 'markdown';
-      setCurrentFileType(contentType);
+      setCurrentFileType(contentType.join('/'));
     } else if (file.name) {
       // If user's machine is missing a valid content type registration
       // for markdown content: text/markdown, file extension will be used instead
diff --git a/ui/component/publishForm/view.jsx b/ui/component/publishForm/view.jsx
index 4081f1168..7a180b98c 100644
--- a/ui/component/publishForm/view.jsx
+++ b/ui/component/publishForm/view.jsx
@@ -208,6 +208,7 @@ function PublishForm(props: Props) {
     isNameValid(name) &&
     title &&
     bid &&
+    thumbnail &&
     !bidError &&
     !emptyPostError &&
     !(thumbnailError && !thumbnailUploaded) &&
diff --git a/ui/component/selectThumbnail/view.jsx b/ui/component/selectThumbnail/view.jsx
index 2076c416c..06b685269 100644
--- a/ui/component/selectThumbnail/view.jsx
+++ b/ui/component/selectThumbnail/view.jsx
@@ -106,7 +106,7 @@ function SelectThumbnail(props: Props) {
         __('This will be visible in a few minutes after you submit this form.')}
       <img
         style={{ display: 'none' }}
-        src={thumbnail || ThumbnailMissingImage}
+        src={thumbnail}
         alt={__('Thumbnail Preview')}
         onError={() => {
           if (updateThumbnailParams) {