had a quick play to see if i could recreate the problem.
img]http://i544.photobucket.com/albums/hh350/jme_73/sig.jpg[/img -I REMOVED FIRST AND LAST SQUARED BRACKETS TO SHOW ACTUAL CODE
gives me this
If i change the address to your file
I get the same error
So I took the basic link from your post, saved the file to my desktop and uploaded to photobucket.
code is now
and gives the right image
so it could be your image host not liking the file linked from another site, or could be just needs resaving and uploading again.