This directory contains all graphic files for your game:

• jpg and png formats are recommended, gif is also accepted
• do not use subdirectories
• use the “CSS sprite” technique for faster loading
• use a reasonable resolution for the web and compression

Typically, this directory should contain less than 10 files (beside box graphics and publisher images), with no file larger than 4 Mb.

See: http://en.doc.boardgamearena.com/Game_art:_img_directory for more details.