Is the image your trying to load a tad to big ? if it is re size it , i store my pics in the windows picture thing & then i click on the pic & go to edit , choose stretch & skew alter the percentage say to 70% in both horizontal & vertical , then save it , if its still to big do it again & just do a small reduction each time till it accepts it as an avatar on here.
Clear as mud i know but it works trust me