Most of the image hosting service put a limit on images so more number of users can be supported. I had seen a max of like 3 MB when it comes to free services.
PiccDrop is one of the free image hosting service which allow you to upload images upto 6 MB free and it supports most of the formats like jpeg,jpg,png,tiff,bmp,gif,ico,icn,svg,pdf,icns,hdi,psd etc.
The service has nothing much if you are looking in terms of features except that its more like file server. Just upload and Link it directly on a website.
They look promising with clean words an ideas they have mentioned in FAQ and Terms and Conditions and I would suggest you to give it a try. We cannot predict the future but we will definitely track this one.