Player Tokens

Couldn't find any way to upload token as a player - is it even possible or "Art Library" is only for DMs to use?

No, it's not possible to upload anything as a player.

You can input an image for a character you control in the avatar section of the journal entry. <a href="https://wiki.roll20.net/Journal" rel="nofollow">https://wiki.roll20.net/Journal</a> The DM can then drag and drop that image to the board and set it up as a token if he wants. You can also just send a token to the DM over Skype thats what most of my players do.