Look at the actual image from the camera, before using a retouching program. Many reviews will have samples of actual output. Unless the images will be used for printing in magazines and such, the resolution on most midrange cameras should be fine. The size of a camera can be important if portability is an issue. A larger, heavier camera is not as easy to take along.
Cameras range from a few ounces to several pounds.
Some, like the Casio cameras, are small enough to fit in a pocket. The number of images may not be a problem if you are shooting near your computer, but if you plan to take your camera away from your computer, make sure it will store enough images. These cards are not inexpensive, but they do give the flexibility of allowing you to change cards and continue shooting. Many midrange cameras are about the equivalent of an ISO 100, and don't shoot well in dim light. Upper end cameras vary a lot in the ISO equivalent, so you may or may not really need a flash.