Stop compressing image on Android

I download image (PNG) from the server and i want to use it like a mask to my shader. This image contains colors in rgba: (1,0,0,1), (2,0,0,1), (3,0,0,1), (4,0,0,1) etc. Every single shape in this image has different color. But when i display this image on screen probably texture importer compressing that. Does exist any option to switch of compression of downloaded image? The second problem is to set Max Size of downloaded image and display it. Is it possible to set max size dynamically?

It's really necesarry for me because without these things colors in image are mixing, for example color (1,0,0,1) is treated like (0,0,0,1) etc.