Hi, I am uploading images to a server to be used as profile pics similar size to those on facebook, however I don't know much about images etc. so could someone suggest the maximum size I allow people to upload? I want the pictures to be high quality but not a ridiculous size

Thanks

In FB you can upload images up to 2048 pixel per side, those will be resized to 960x720, which is the max size in the lightbox. But everything depends on your target and in the usage of these images inside your application. If your app, for example, needs to handle compositions and go to print them, then you can get images over 30000 pixel per side.