Understanding Bit Depth, Color Depth, and Color Gamut
If the fineness of an image is your concern consider some time understanding bit-depth, color depth, and color gamut. So that you know what happens to an image while you make an edit, how much it can tolerate and how far you can go with certain types of files.
Although it may sound very technical the ideas behind bit depth, color depth, and color gamut are fairly simple. Here you can learn how they contribute to the quality of your image.