I use Safari and I can update my profile info no problem, but error out trying to upload a pic.
Safari/WebKit/Konquerer has historically enjoyed compatibility problems with some WYSIQYG editors and javascript implementations. Unfortunately, its market share isn't big enough to prompt enough devs to do much about it:
When will vBulletin WYSIWYG work with Safari? - vBulletin Community Forum
"I checked this out at the start of the 3.7 process to see how realistic it was to get Opera and Safari compatibility. The short answer is that our wysiwyg code is overly complicated and adding more browser specific sections would make it worse.
There wasn't a quick way to do it, I filed some bugs with Opera regarding there implementation and Webkit has some tracking ones."