Noob question: how do I compress an ISO?

[Petruza]

I've seen ISOs (totally legal) that when compressed with rar are 200MB, but when decompressed, are the whole 4.7GB
Can I compress the ISO and still play it with Dolphin? how?

[Starscream]

You can right click on the game while in the Dolphin game list and select "compress ISO", but the size it will compress to will vary depending on the game.

[Petruza]

Thanks!