I've been having trouble with the popup for inserting images into posts for a while now. I solved it by switching to a new browser. I can't insert images from Firefox anymore but Safari has no trouble.
Hmm. Well, it looks like that or something very similar is in their open support request queue (open meaning they haven't addressed it yet). You might want to send them your own issue so they know it's not an isolated problem. http://www.livejournal.com/support/see_request.bml?id=1661282
Have you tried clearing your cache? That's all I can think of, otherwise.
no subject
Date: 2013-08-05 03:55 pm (UTC)no subject
Date: 2013-08-06 03:10 am (UTC)no subject
Date: 2013-08-06 05:07 am (UTC)http://www.livejournal.com/support/see_request.bml?id=1661282
Have you tried clearing your cache? That's all I can think of, otherwise.