Question: are all jpegs 8 bit?
Answer: Well, a JPEG is an 8-bit image, which means that it uses 8 bits per color channel. There are 3 color channels, which means that a JPEG can contain up to (2^8)^3 = 256*256*256 = 16777216 different colors. So a JPEG can contain about 16.8 million colors.