This time my question is the following: I want to upload images using a file input and instead of refreshing the whole I site, I want a simple AJAX loader to roll and after
You won't be able to upload a file using Javascript(AJAX). I'm not sure of HTML5 features for uploading, but if you are looking to do an upload for desktop browsers you'll have to use plugin-based software. Something like flash or java will be able to upload files without submitting the file to a new page. I'd look into pre-build solutions that will work for what you need.