…and the “Other” Category
JPEG (joint photographic experts group)
JPEGs (shortened to “JPG” on a PC, as a maximum of three letters is allowed for the file extension), like TIFFs, can utilize a range of up to 16.7 million colors in RGB format and 4.5 billion in CMYK. However, unlike TIFFs, JPEG is a lossy format, which means that, at whatever quality level you choose to save it, you are losing information that you will never get back. Each time the image is resaved, you lose a little more. At a high-quality level, this is not a huge problem. At a low level, it is horrible.
If you save a file as a JPEG you have the option of selecting, in Photoshop, any one of thirteen quality levels (0 to 12, 0 being the lowest). To see for yourself what a lossy ...