God this thing is giving me some crazy error that I cant post my image up. Something about not being allowed to post a certain extension, even though the picture is .jpg (???)
I just had that error crop up when trying to link a photo of the peppermint loach, are you linking the photo from a photobucket account or straight from the internet?
EDIT: not sure about you others but make see if the photo is used on a website that is blocked from being mentioned on this forum
for example, the loach photo I wanted to link although from google search, was originally on a certain loach forum which I suspect is filtered on here..
Right click on the image (where it came from originally) and go to properties. Near the bottom it will give you the direct url for the photo, it has to end in .jpg to work.
The one I was trying to link ended in .jpg/image_medium which is, I think, why it didn't work. I think if you use a picture from google images and move it to one of your accounts like photobucket, it might then appear with just the .jpg url but doesn't mean it will work.
Resort to default, log out, clear history and cookies etc and log back in failing that... restart computer.... failing that... thump it really hard and curse at it a bit!