Things You'll Need
Mod Podge -- your choice of finish
3/4-inch bristle brush
Mod Podge is an all-in-one glue, sealer and finisher product. It is used to decoupage a variety of craft items including photos, tiles, fabrics and papers. Different finishes are available including glossy, matte, glow-in-the-dark, sparkle and outdoor. Mod Podge can be used to affix photographs to glass tiles for simple projects, or as part of more complex picture, tiling or building projects.
Prepare the glass tile, by cleaning it thoroughly. If the surface is very smooth, roughen it up a bit with the sandpaper. Sand the area where you'll be placing the picture, until the surface feels slightly abrasive. This texture will help the glue take hold. Wipe off any glass dust after sanding.
Apply the first Mod Podge coat. Brush it on both the glass and the back of the photograph. If any bubbles appear in the Mod Podge, brush them out smooth. Lay the picture down on the glass, and carefully hold it in place while using the squeegee to smooth out any bubbles that appear. If it slides around a bit, just move it back to the proper position.
Let the Mod Podge dry for at least 15 minutes. Double-check for any air bubbles, and smooth them out. If the Mod Podge is still wet, the picture may slide around again, so be sure it is as dry as possible before touching it.
Use the brush to apply another coat of Mod Podge. Let it dry thoroughly.
You can use a foam brush to apply the Mod Podge to the glass and back of the photograph, but it may leave air bubbles that you will have to smooth out with the bristle brush.
Wear gloves when sanding the glass tile and be sure to clean the tile and the area thoroughly before removing the gloves. Throw them away immediately after using so that you don't get any tiny shards of glass on your skin.