Avoid Using Copyrighted Material
One of the biggest advantages to using your own photographs is that you do not have to worry about whether the photograph is copyrighted or not and you don't have to seek out the owner of the photograph to request permission to use it. As the person who took the photograph, you own the rights to it.
Getting People to Pose for You
Two of the most common ways to get posed photographs is for either the blogger to make the pose (such as sitting at an office desk) and having someone take the photograph or having a family member or significant other make the pose.
Hiring someone to make poses for you requires a contract the specifically states that the photographs you are taking will be used for such and such, that you have the rights to use these photographs, and that you are paying the model X amount of dollars to pose for these photographs. You can find samples of modeling contracts online.
I take a lot of nature photographs because there is not contract involved in taking them and no people. I can tie in just about any outdoor photograph into my blog post. I also take a lot of pictures of steps to represent "the steps to" something or other.
Take a lot of scenery photographs. Views of mountains, the ocean, and the dessert can easily be tied in to any subject you are writing about.
Old Vacation Photos
Put those old vacation photos to use! I've scanned in oodles of old vacation photos from my childhood (I was taking photographs back then, too) and old vacation photos from my relatives. I've created an immense back stock of family vacation photos that I have been using in my articles whenever I can tie one in.
Take Your Camera Everywhere
I have a back log of thousands of photographs because I take my digital camera with me everywhere I go. What I do is keep my backlog of photographs in subject organized files and about once a month I will go into them, select 200 photographs to resize for the internet, and place these resized photos in my "use online" file. I use each photograph about 2 times, in different blogs and articles on different domains. The photographs that are exceptionally good get burned onto a disc in case I ever want to use it again. Generally, though, I have far too many photos to hang onto them all. I use each twice and then delete.
Protecting Your Copyrighted Photos
Sadly, it is nearly impossible to prevent your photographs from being used by others. The truth is, most people who grab photographs from a Google search don't understand copyrights. They aren't doing it maliciously, but out of ignorance of the law. Instead of fighting the copyright battle on a daily basis (and wasting a lot of your time), add your domain name onto the picture. Most people will not bother to edit the photo and use it with your domain name on it. This gives you free advertising. On the other hand, if some bozo takes your photographs, removes your stamp on them and then uses them on his own site, you can bet your bottom dollar that he has a basic knowledge of copyright laws and he being a douche. Contact him about the copyright violation. If he doesn't agree to your terms (either remove the photograph or use it in its original form with your url), you can contact his hosting provider about the copyright violation.