Are u getting error 500?
This is a problem with more devices as cameras get bigger and screen shots get larger file sizes.
Most pic posting errors occur because the file is too large.
On my iphone 4s a screen shot file is small enough to post but any pic i take with the cam has to be dumbed down or resized.
I do this by emailing the pic i want to post to myself. My phone asks me if i want to send the original sized file (huge) or large, medium, or small. I send it medium, open the email, save the pics to my film roll, then am able to post those pics.
Hope this helps.