hi i have png file 3000x3646 . i am adding in unity but it is look bad. and writing 2048x2048 at the photo information in inspector. i builded for my iPhone and it is look bad at the iPhone.
What do you mean look bad? Do you have a screenshot? Unity will set textures to be power of two by default(20148x2048 for this case). You can change this by using the Advanced option in the texture importer.