Daz Studio is a 3D posing and rendering application made by Daz3D. It can be used to render single images of animated sequences. Daz Studio comes with a number of tools and features to help you create an environment for your characters. Some of these are more complex and sophisticated, such as the Environment props that reproduce a full scene with high fidelity. However, if you simply want to place a photo image on the background in Daz Studio, the process is quite simple.
Load the photo that you want to use onto your computer.
Start then Daz Studio application.
Select "File" from the menu and open a scene you have created to which you want to add the photo.
Select "Edit" from the menu and choose "Backdrop." In the dialogue that appears, click on the button next to "Image" and then click "Browse." In the dialogue that appears, locate and select the photo you loaded. Click "Accept" to apply the photo. Save your work.