Everyone likes to document their progress while fishing, and to take a photo of your latest catch is one of the best ways of doing that. Although to take a really good photo of your latest catch requires some skill.
Try to include in the photo a recognisable object to give a sense of scale. This could be yourself, a ruler whatever you want!
This leads me onto my next point; if you are going to be in the photo, and you are fishing alone, you will need some sort of tripod in which to position your camera while you get ready. Many digital cameras come with a time delay in which you can get ready with the fish before the photo is taken.
Try to make the background of the shot as scenic as possible. This just adds to the beauty of the shot. Personally I find if any interesting weather or season change (red leaves on trees for example) is present this makes an exceptional interesting photo.
Obviously try to keep the time the fish is out of the water at a minimum. There are commercially available keep-nets for carp and pike but again these are not beneficial to the fish.
The use of photo editing software after the photo has been taken can correct errors such as blur or over exposure. A popular free tool to do this is Google's Picasa
