Photoshop Mosaic Effect Tutorial
Start with a colorful image, any size. For this tutorial I chose a flower in bright colors and cropped it to 500x500 pixels. Place the picture on its own layer for manipulation purposes.
Create a new layer. Call it Mosaic. Fill it with black. Place the picture image above the Mosaic layer, and set the opacity to about 50%.
Click on the Mosaic layer. Now, you are going to start making the grout and cracks that will make up the mosaic. Select the delete tool and choose a 5 pixel round brush. (You may need a larger brush if you are working on a larger image.) Proceed to delete in a tile-shaped pattern. Pay attention to the picture, so you can tell where to make appropriate seletions on the Mosaic layer. Let the colors of the original picture be a guide to how the tiles should be shaped.
Once you have completed this step, switch to a 1 pixel round brush to make the cracks. You don't have to add very many, but the really do alot for the final look.
Once you are done making grount and cracks, ctrl-click the Mosaic layer to get a selection of your tiles. Now, Select->Inverse or Shift-Ctrl-I and click on your picture layer. Increase the opacity of the layer too 100%, then hit delete to delete the grout selection from the picture layer.
Now, create a new layer and put it behind the picture layer. Then fill it with a grout color of your choice. I chose #CDB189. To make the grout look grouty, go to Filter->Noise->Add Noise.Use the settings in this picture.
Now, for the finishing touches, go to Layer->Layer Style->Inner Shadow. Use these settings. Now, click back to your picture layer. Go to Layer->Layer Style->Bevel and Emboss and use these settings. There you have it! One mosaic picture.
To finish this off, I added a glare and did a bit of darkening with the burn tool. To see a larger version of the finished picture, click the thumbnail on the left. This technique works best on images with bright colors, but can also work well on just about any picture that has alot of detail, like a close up of a persons face.