I have used search but couldn't find the answer I'm looking for. I'm just learning about photography and have a query regarding 100% crop. On the Mac, if I open up an image using preview and click actual size from the menu I assume this is the 100% image size? If I then use the crop function (select a section then choose crop from the menu) how do I ensure that I save this without compression? When I go to save there are several options. I assume jpeg will compress, but do any of the other options save without compression such as jpeg 2000, png, tiff? Assuming I can save without compression, having done the above would this be a 100% crop?