Eric,

 

I am unable to right click on thumbnails.  Nothing happens when I attempt to right click on the red X.  I can add the images and they show up properly in the editor.  It's odd that the thumbnail is displayed as red X; which makes me think that it cannot find the image.  However, when I move the mouse of it - I can see the image and I can insert it into the editor properly.  Please let me know what else I can try.

 

Thanks