Saving a Texture makes it go pixelated

Whenever my texture saves it becomes pixelated.
I can fix it by simply refreshing one of my drop down options. But re-saving presents the same problem.
My texture is for channel masking.
First image is before, second is after. (Look around the shoulder area)

Thank you in advance of any suggestions.

David

Compressing merges RGB a little bit, which is often the reason for noticing square-ish artifacts like yours.
If its only a grayscale texture, set the compression to alpha, or one of the RGB8 ones.
Keep in mind that uncompressed is bigger in filesize, but due to it being uncompressed you occasionally can get away with a smaller texture.

let me know if that helps.
Additionally, if it doesnt, please show the texture in question.