There are at least three different file formats that a digital camera can use to save a photograph to a memory card, but the most popular and usually the factory default is JPEG, an acronym for Joint Photographic Expert Group!

The main feature of a JPEG image and an advantage for many amateur photographers is its ability to compress an image to save space on the memory card allowing more images to be saved. However, the amount of compression, which is a highly sophisticated and complicated process, can be varied, affecting the capacity of the memory card.

Different cameras even within the same stable present this information in a variety of ways. There is no standard, so for more precise information the photographer has to consult the instruction book, which is often presented as a table that include the other file formats TIFF and RAW.

Broadly speaking, the more an image is compressed to increase the capacity of the memory card, the more noticeable will be a reduction in its quality. A heavily compressed image is useful for emailing and prints up to postcard size, but anything larger demands a better quality image with less compression to preserve its sharpness and colour. At this higher quality setting the capacity of the memory card is reduced. Photographers with computer skills usually save their images at this best quality setting and then exercise the option to make a copy, downsizing it in Photoshop for emailing.

It should be noted that a high quality photograph saved as a JPEG file with the least compression is not suitable for emailing, whereas a JPEG image heavily compressed for emailing is unlikely to produce a quality enlargement. Photographers who do not possess computer skills need to make some important decisions first and set the required compression for its use before a picture is taken.