if you are trying to UPLOAD your own avatar and it doesnt seem to be working...if you simply resize it smaller (say around 400 pixels in width and SAVE it to your computer) and THEN try to upload it again...it SHOULD work without any incident.
If you dont have software to resize the pics you can use this online website,
http://picresize.com/1- upload the pic from your computer or disk (click continue)
2- on the next screen in step #2, resize.... change the drop down to CUSTOM , then enter 400 in the box and change drop down box from percent to pixels
3- skip down to the bottom and do SAVE AS JPG and hit the IM DONE RESIZE MY PIC
on the next screen do SAVE TO DISK and save the new image file to your computer (remember where you save it...)
then you are ready to UPLOAD it as your avatar to the board!!