//no, but e.g. if you do not have the default skin, because you use a mod all, other skins are shown as one skin. May be it's using then a skin name which is similar to default.png. Sometimes I see some players online, who play with "my" test.png.
this is wierd, because i do have this default.png file, and worse i retryed 5 min ago, and 4 users had my unpublished skin haha now i'm sure it's a bug, or else it spreads like plague ^____^
//the skin thing is case sensitive you probably saved your skin as default.png or some other common name
not really, it was a custom name, with a lot of number at the end of the filename (i did a lot of tests ^^)