The user icons we use on the site are ideally square, 100 x 100 pixels and less then 100kb in size, jpeg files.

To set your user icon for your ACP/ACE cosplay profile, click
http://www.acparadise.com/acp/tools.php ... &s=profile or
http://www.acparadise.com/ace/tools.php ... &s=profile
Click browse and upload the icon

To set your user icon for your ACS photographer account, click
http://www.acparadise.com/acs/tools.php
Click Edit Profile
Scroll to the very bottom and upload one on the lower right

To set your ACP forum avatar, click
ucp.php?i=profile&mode=avatar
and follow the appropriate instructions.