Way to create different size sprites?

Hi, I understand that you can change the sprite png files. But is there a way to make each individual sprite a different size?

Also, in a different thread, I noticed that you mentioned another plugin (custom-assets-dinosaur-game.zip) that can help any custom sprites remain, even after the main plugin is updated. How would I use that separate plugin? Do I upload both the main game and that 2nd plugin? Do I only change the sprites in the second plugin? Thanks!