What STERBEN said is partially true. Right now when you join the server, the game will not load the avatars of players who were already there, but it will start loading avatars of players who join after you.
The reason for this is to reduce memory usage and also to prevent ping spikes when loading many images at once (It will be back to normal once multithreading is added in WebGL).
However in your case it seems like a bug, your avatar was already loaded so it should also appear in the final screen. Will check it soon.
