Once in a while, I get asked for good locations for photo shoots where one can rez a few props. It's surprisingly difficult to find such places—obejct rezzing in most regions generally being turned off, or at most limited to a couple minutes—but one possibility is Image Essentials, where anyone can build without time constraints. Around the sim are a number of naturalistic settings such as those shown here, and they're certainly workable as backgrounds for portraits.
You'll find areas such as woodlands, a Japanese garden thick with bamboo, a dark, haunted looking spot, and so on. In the center of the sim, a number of studios provide interior settings for images with a variety of scenes and poses, with separate studios for female and male poses, as well as for families and groups. (Join the group to use the poses.) All of these locations are available for free use; the sim is also home to the shop Image Essentials, and there you can find an assortment of props and poses for photography.