Blurred textures

I am Developing A game for iPhone. I am using some textures which is use them in the Gui textures as buttons.

Textures Detail

Format : PNG Pixel/inches: 72 Alpha : Enabele Size : power of two

Problem is that When I build ( having checked the "Compress Textures" option) the project some textures(Which contain more alpha portion) get blurred and also when i install on iphone these are seen blurred.

Please Help if someone knows!