@lololulu19 I'm no technician at all but, according to Wikipedia, .jfi/.jfif seems to be a slight variant of .jpg: the algorithm used to compress the image is the same but extra info is store differently (as far as I could understand).
As for other file formats I have also experienced positively the upload on gaytor.rent of files with extension .heic (which is Apple renaming for .heif).
While JPEG algorithm is lossy, .heif can be set to encode losslessly, as for .png (while producing smaller files than .png).
Also, .png has a nice advantage over the former formats: it can preserve transparency. A feature which is however useless on gaytor.rent since every uploaded image is automatically converted to .jpg (and transparency → white…).