Image Dimensions

A pro tip from Unity2D Game Development book:

Images for your video game, as you most likely already know, work best if they are always a power of two (2,4,8,16,32,64,128,256,512,1024,2048), because the video card requires image map to be a power of two. Otherwise, the image map will automatically map to be a power of two by the game-engine. While this is not as noticeable in 3D games with mapped imageries, in a 2D game where the 1:1 art for the image map is quite important, it can easily look stretched or blurry.

Source: Unity2D Game Development, Calebrese, D,pp.9

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