I was having an issue in Firefox 2.0.0.11 where the TinyMCE images were not displaying in my posts or pages wysiwyg editor. I was getting frustrated because there seemed to be no solution. My gut told me the images were corrupted and not the JS code. So I went to wp-includes/js/tinymce/themes/advanced/ and deleted the images folder. I then re-uploaded the folder with my transfer preference as auto vs. ascii. I then changed the permissions on the folder to 755 and logged back into my admin screen.
The images appeared just fine in the tinyMCE and now my wysiwyg editor function is working fine. Not sure if this will work for others, but it worked for me.
