What size can textures be?
Textures must have power of two dimensions less than or equal to 1024 e.g 2,4,8,16,32,64,128,256,512 and 1024. So 16×256 is okay, 512×512 is okay but 240×320 is not. Additionally if you want to use compressed (PVRTC) textures they must be square. You can still use an image that does not follow these rules but beware that it will be stored in a texture with power of two dimensions. So loading a 240×320 images will result in a 256×512 texture being created. On newer platforms (such as iPhone 3GS) a maximum texture size of 2048×2048 is supported, however, the Texture2D class that performs texture loading has a hard coded maximum of 1024.
