How could I save a image as a text file?

Sorry, I am not very experienced with programming and such, but I am wondering if it would be possible to convert an image to a text file. One idea I had is to look at the color of every pixel and save the HEX value of the color, then to decode it by printing out the HEX values. I don't know if this is a good way to do it, or if other ways already exist.