Have a good website with many good incoming links? That'll probably help. Other then that, I don't think there is anything special you can do.
Since search engines can't describe photos it may help to have a descriptive filename to these photos.
You name those files with keywords. Example, if someone is searching for dogs, you name it my-dogs.jpg Then you may put keyword (dogs) in title tag, put text around a picture with keywords. Then put alt tag with keyword. Link to that picture from different places on your site. And that' it .