A one-gigabyte memory card holds between 13 and 715 pictures at one time, depending up on how many megapixels each photograph contains. A card can hold more compressed files than raw photographs that haven't been compressed for easier storage. For example, a one-gigabyte memory card holds 715 compressed picture files if each photograph has four megapixels. The same capacity card holds 13 raw photos at 22 megapixels each.
For Kodak memory cards, a one-gigabyte card holds 260 six-megapixel photographs and 45 16-megapixel photographs. Sandisk cards contain up to 71 raw, unprocessed photos at four megapixels each. The same capacity can hold up to 715 four-megapixel photographs in compressed form.
The difference in memory storage is based upon the size of each saved file. A compressed four-megapixel photograph requires 1.2 megabytes of memory, versus 12 megabytes for a raw photo with the same megapixels. If a removable drive holds more memory, more pictures can potentially be stored on the disk.
A megapixel, abbreviated as MP on digital camera specifications, refers to the resolution of the photograph. One megapixel is equal to 1 million pixels, and a pixel is smallest individual element of one photograph. A digital photograph with 10 megapixels has a higher resolution than a photograph of five megapixels.