Question: how many megapixels in 1 mb?
Answer: There is one of these 8-bit values each for Red, Green, and Blue. So, a 6 megapixel (MP) image would occupy 6,000,000 pixels x 3 bytes or 18,000,000 bytes uncompressed (i.e. 18 MB). Generally speaking, the more megapixels a digital image contains, the more megabytes (MB) it will consume on a hard drive or memory card.