Things won't upload

I've been trying to upload various different photos. I haven't been able to post for at least a month if not longer because nothing will Upload. I don't know what the issue is because everything formatting seems to be correct for the website. Everything gets stuck between 90-98% uploaded. I try to reupload and it does the same thing.
I've logged out and logged back in and that didn't fix it either. I can't mass upload OR single upload.