NPOT : not power of two.
In mathematics, a power of two is a number of the form 2n where n is an integer, i.e. the result of exponentiation with number two as the base and integer n as the exponent.
When i was making my game, i see that some sprites or textures that not NPOT (not power of two) wont be compressed.
now i know why, so i share this video to help other Beginners.