This panel let you record animated gifs of your game!
Snapshot will capture an animated gif of what is currently showing in your Room panel, sized 512x512 pixels. You need to click "download gif" to download it, it won't start automatically.
This is an example taken from a Bitsy game with the Record gif tool
With "Start recording" you can record a longer clip of your game. Go to the Room panel and click "Play", get to the point that you want to record, click "Start recording", play your game then click "Stop recording" when you're done and click "download gif". However, be warned that this can create very big files!
Secret knowledge: if you keep your ALT key pressed while you click snapshot, you will instead get a 726x576 gif, which is the right proportion to use it as a cover image when you upload a game to itch.io! To do that, it adds a frame of the background color around the square image you see in the Room panel. Here's a couple of examples: you'll notice that in the second one, it's much more noticeable.
Go back to Basic functions to learn more!