Normally digital cameras can as a minimum be setup to shoot photos in the following dimensions:

640 x 480
1.280 x 960
1.600 x 1.200
2.048 x 1.536

If you choose the highest quality, your digital pictures (jpeg-format) will be about 1,5 MB pr. photo, and then you will be as safe as possible.

If you want to see the pixel-size of a photo, then right click on the file and choose properties. Then you should select the pane “document info”. A proper print quality should have at least 300 dpi, which is 300 pixels pr. inch – i.e. you need to look at how large a picture you are printing in order to determine if the number of pixels are good for printing.