I made an avatar of my cat and I happily went to upload it. It was 100 x 100 pixels and I made it on Paint, so I assumed that it would be fairly small. However, it told me that the file was 24 KB! How can I change the file size of my avatar? It is 100px x 100px, originated from a photo of my cat that was resized and given a border on MS Paint, and saved in .PNG format.