In addition to the above, I've run security scans on my laptop, and have no viruses and the like. I've also disabled ad-blocker, and my other add-on's. As I said before, I am trying to upload my artwork, so there shouldn't be any sort of copyright issue, and I know which file types and file sizes I can and cannot upload. I'm running Windows 7 on a 2012 Toshiba, and just started having this issue last night. Also, this isn't only happening on Firefox, I've tried Chrome and IE too.