I have the Maxx HD but i think the process is basically the same if I remember correctly. By default I believe your photos are stored on the internal storage. But moving to your SD card is easy.
Look for the app "Files" or "My Files" now open the "Device Storage" you will see a folder labeled "DCIM" this contains your camera photos. Open this folder (DCIM) then Long press "Camera" this opens the option to delete, move, copy, rename, or compress the folder. In your case I would just copy it the go back to your SD card and paste.
Its pretty easy to figure out. Let me know if you have any questions.