What resolution and size should my photo have and how does this relate to its quality?

If you look at a picture under a strong magnifying glass or microscope, you can see that it is made up of small dots called pixels. The sharpness, or clarity of a photograph and therefore of its quality, depends on the amount of pixels it has. The more pixels a photograph has the better the quality. A high resolution photo gives a more detailed picture than a low resolution one. If you use one of you own photos, it is also important that they are in focus, as we can not print an out of focus photo better than it really is.

Professional photographers and printers use the expression dpi (dots per inch) to determine the resolution of a photograph. Your photo must have a resolution of at least 150 dpi to be sure that it will print in a high enough resolution.

In most standard computer photo editing software e.g. Windows Picture Manager, it is possible to determine the size of your photo and the format in which it can be saved.