Save image with alt-s while texture painting in 3d-viewport

Right now while texture painting, it is a bit of a hassle to need to move your cursor into the image editor area to save your image. Alt-s normal clears scale in the 3d viewport, but that isn't a thing in texture painting. Right now, best I can tell, alt-s in texture paint mode does nothing. It should either save the image you are painting if you have single image selected, or save the selected image texture in the material nodes if you are in material mode. I think you can do this with a custom key map, it just seems like to good of an idea to need a custom change for.