Trouble with 'BYTE SIZE for AVATAR'

So How Many BYTES must an AVATAR be to get uploaded

-- no matter how SMALL I make a pic the message still comes up that is has Exceeded the Byte Size and will not allow me to have an AVATAR

-- Please Advise ! PS -- I FINALLY got INTO this Site after many attempts

-- I changed my E mail to my second E mail and user name a bit and got finally accepted to show my NIKON SNAPS !