403 on image files when using subdomains

This has been quite annoying over the past few days as, I've installed (through Softalicious) some different applications for my site and have used subdomains with them. Over these last few days I've started noticing random 403 errors occuring for mostly image files, but not all image files. Attempting to directly link to them doesn't work and in the File Manager I've even set the image file, and the directory (and the ones proceeding them if necessary) to 777, which means it should be virtually impossible for a 403 to be returned, right? For instance, tonight on this forums software I installed (FluxBB, never had this 403 problem before in the past; ever.) on a subdomain, and when I went to upload a custom avatar for myself, it worked fine and dandy, but, now the avatar cannot be accessed as it returns 403, but the index-preventing index.html file in the same exact directory can be accessed fine. Is there something wrong, possibly with my website configuration? I'll review it all as maybe I've tampered with something I shouldn't have. Also nothing in the error logs. And I'm not using WHM, rather shared VPS cPanel hosting. Here's what I see: 56149