I think the size is 52.6KB(53,939 Bytes) Should i make the picture smaller? If so, what would the Width and Height be in pixels?

I've been trying to add a picture for my character, Kenjatsu and the rules say i can only upload pictures that are JPG, JPEG, GIF or PNG. The Picture im trying to upload is 359(width) 294(Height) in pixels. im saving the picture in JPG, JPEG, GIF and PNG but the picture still wont upload. Is there s...