That's a cute idea! Super glue those glass rocks you can buy from the Dollar Tree onto a flat surfaced picture frame, add embellishments. *** make the photo things with the rocks and then glue those to picture frames or letter shapes.
Creative Ways To Use Wood Frames - if you're decorating your space on a budget, using craft store or thrifted frames and a can of spray paint is a great way to start! This post has some cute ideas - Craftaholics Anonymous