Wooden boards work great for this project, as do wood disks with the bark still showing. If the surface has a rough finish, sand it down with medium to fine-grit sandpaper. This will make it easier to transfer the picture. Since you'll only be transferring the photo to one side of your wood piece, you will have the raw edges showing. You can leave these plain for a rustic touch, or you can paint them with 1 to 2 coats of acrylic paint for a nicer touch. Let the first coat of acrylic paint dry before applying the next one. If you want the image to be opaque, without the wood grain showing through, you must use Mod Podge Photo Transfer Medium. If you want the image to be translucent with the wood grain showing through, use regular, matte Pod Podge. Do not use an ink jet printer or photo paper, otherwise this method will not work. You must use a laser printer and regular printer paper. If you do not have access to a laser printer, use a laser photocopier instead.  Your picture will come out in reverse. If this bothers you, mirror it first using an image editing program.  If your image has a white border, it might be a good idea to trim it off, especially if you are using photo medium. You can use a wide, flat paintbrush or foam brush to do this. Make sure that you are applying the Mod Podge to the front of the picture, not the back. Also, make sure that you are applying a thick, generous coat of Mod Podge. Run the edge of the credit card or boning tool across the back of the picture. Work your way outwards, starting from the center. Use a damp cloth to wipe up any excess Mod Podge that leaks out from under the edges of the picture. Allow the picture and wood to dry for 24 hours first. Once it is dry, cover the back of the picture with a damp rag. You are ready for the next step once the paper becomes wet; this will take about 5 minutes. You can do this with your fingers, a damp rag, or a damp sponge. Use a light touch and circular motions; if you press too hard, you risk rubbing the image off entirely.  Rinse the wood under the water often to get rid of any clumps of paper.  If there is any residue, let the wood dry, then repeat the process. This should only take an hour. Once it is dry, you can proceed to the next step. You can also weather the image by lightly scratching the edges with sandpaper. Be sure to extend the Mod Podge past the edges of the picture and onto the wood itself. This will help seal it in further. Allow the first coat to dry for 15 to 20 minutes before applying the next one. If you need to, let the second coat dry, then add a third.  You can use Mod Podge in a different finish for this step, such as glossy or satin. Alternatively, you can seal the transferred image with clear, acrylic sealer. Mod Podge typically has a curing time, so check the label to be sure. Once the Mod Podge has finished drying and curing, the wooden piece is ready to use. Be patient; if you use it too soon, the Mod Podge may turn sticky! It is not recommended to transfer images onto multiple sides for this method. If you get the Mod Podge wet, it may melt off.

Summary:
Choose a suitable piece of wood. Paint the sides of your wood piece, if desired. Choose your Mod Podge. Print your picture out using a laser printer and regular paper. Apply a thick coat of your chosen Mod Podge to the front of the picture. Lay the picture face-down onto the wood. Allow the picture to dry, then soak the back with a damp cloth. Rub the paper off of the wood. Allow the wood to dry. Apply 2 to 3 coats of regular Mod Podge. Allow the Mod Podge to dry completely.