As a photographer I can tell you that Al Norris is correct. As soon as you press the shutter release that image is copywrited to whomever made it.
To prevent others from using it and claiming it as theirs you can always watermark your images in a way that doesn't distract from the image, but is easily visible. Just watermark it with your name and everyone will know who it belongs to.
A hit with a .45 ACP beats a hit with a .22 LR everytime. A hit with a .22 LR beats a miss with a .50 BMG everytime.