Not working from Photobucket (just tried that as well!) for me either - very odd, as I've managed to upload here before.
I shall go and find something more useful to do...
1. Go to PhotoBucket.com and upload your pix.
2. Click on the little 'pic' icon here.
3. Click on the prompt at the top of your screen to 'temporarily allow scripted windows...'
4. Select the pic you wish to upload; highlight its URL and click 'Copy'.
5. Come back here: click on the little 'pic' icon again. Now click 'Paste' to copy the URL of your pic into the prompt 'Enter the URL of the image'.
6. Hey presto! - If it works, then you should see the pic when you 'Preview Message' before you go to 'Post message'.