Thanks for your answers,
I have a 8mb limit for each files and 64mb in total for an upload.
up to now I have avoided png as it creates larger files onto my server than jpg does.
regarding below formats, what should one avoid or what format can create harm if uploaded?
I'm thinking formats like gz,.rar,.tar,.tgz,.zip who could contain malicious files
.gif,.jpg,.jpeg,.png,.txt,.pdf,.gz,.rar,.tar,.tgz,.zip
so could it be a good idea to use
.gif,.jpg,.jpeg,.png,.txt,.pdf ? or even remove the pdf option
