hey!i requested a game to speedrun.com and it was accepted,but i dont know how to add a "picture" to the game (this thing:http://prntscr.com/t5o9g2)

Use "Cover" and "Japanese cover" under "Edit Game" to set the game covers.

You can refer to the unofficial documentation here on how to set up a leaderboard: https://www.speedrun.com/the_site/thread/pgxyw

thanks