You can make your own skins, it currently as no size limit ( maybe 1024x1024 pixels is the limit, i've not tested ) , but you should remain with the 286x49 size, cause the colisions are not afected by the image. 

Only .bmp images are accepted by the game.

To have transparent images, put the trasparent color in the down left conner of the image. 

You can also submit your skins to the game forum, fell free to send comments to. 

GAME FORUM LINK -> http://pedrodh.phpnet.us/phpBB/index.php
( look for the cyfut forum )

NOTE: The forum is not yet acepting files, so you have to save them in other website and have a link to the file in the forum so people can see it. One free file hosting is http://www.yourfilehost.com/

, it would be smart to compress the images to a .zip file since only .bmp images are accepted, and they are a big in size.

OFFICIAL WEBSITE :  http://pedrodh.phpnet.us