This one from Olympus even has an underwater case that is waterproof up to 30m. We suggest you stick to NiMH AA rechargable batteries whenever possible. The higher the number of pixels, the sharper the image. It is vital that you understand the definition of pixel. Read more about Pixel Picture quality - compression Compression can drastically reduce the file size.
Compression also makes the picture less sharp.
A good compression rate is the best compromise between these two considerations. Another factor that also effect picture quality is pixels. A 3 million pixel camera can produce picture quality that is almost identical to film, to the naked eye. Some digital cameras can record brief audio messages. Digital cameras are superior for operating in low light environment, such as for astronomy photography.