Every platform shows your avatar as a small square or circle, but each asks for a different upload. The table above compares them: the size ImgWrench exports for each one, the formats the platform accepts and its file limit, with a link to a free tool that makes it.
Which size should I use?
Use the size listed for each platform. Twitch publishes an exact size, 256×256; Kick, TikTok and YouTube give only a minimum or nothing at all, so the starred sizes are ImgWrench's picks, large enough to stay sharp. Start from a square image of at least 1080×1080 pixels and every row can be made from it without blurring.
Keep the middle clear
An avatar shown as a circle loses its corners. Keep faces and logos in the middle and leave a little space around them, so nothing important ends up there. Every profile picture tool on ImgWrench has a Circle shape, so you can see the round crop before you download.