I had a big piece of tempered glass from an old bulletin board that I wanted to re-purpose into something instead of throwing it away. I also wanted to put some of my pictures on display, so this is what I came up with.

Step 1: Tools and Materials

To make one of these, you will need the following materials:
A piece of plate glass, (tempered is probably best if it has any size to it).
Mirror mounting clips (available at any hardware store)
Photos
Poster Board
Spray Glue
Photo mounting corners

You will also need the following tools:
Tape measure and/or ruler or straight edge
Carpenters level or laser level depending on how well aligned you want everything
Stud finder
Drill/Driver or hand drill and screwdriver

Optional: A glass cutter if you need to cut your glass to a different size. Do not try to cut tempered glass!

Step 2: Locate Studs and Install Mounting Clips

Use a stud finder or other means to locate the wall studs. I do not recommend using drywall anchors for this job unless it is a really lightweight piece of glass. The last thing you want is this falling off the wall.

Use your tape measure, straight edge, level, laser, or whatever measurement tools you have at your disposal to lay out the mounting clip locations. Follow the instructions that came with the clips to allow the proper offset to fit the piece of glass you are trying to support. You want the bottom line of clips as straight and level as possible so the glass sits in them right.

Pilot drill a small hole (smaller than the mounting screws) at each clip location to make sure you are hitting a stud. Adjust the alignment if necessary.

Screw the mounting clips to the wall with the screws provided with the clips. The spring loaded clips go at the top and the fixed clips go at the bottom.

Step 3: Test Fit the Glass

After securing all the clips, test fit your piece of glass. Get someone to help you if using a large piece of glass. Tip the top edge of the glass back into the top clips. Push up on the spring loaded clips and tip the bottom into the bottom brackets. Lower the glass into the bottom brackets. Make sure the top clips are catching the top of the glass before letting go. Adjust the positions of your clips if needed.

Step 4: Mount Photos to Glass

Make sure you glass is good and clean. I used Windex and a paper towel to clean off any finger prints or other crud. I recommend wearing some type of gloves when handling the glass from here out so you don't have to keep cleaning finger prints off of it.

Lay out your photos how you would like them on the glass. Make sure they will clear the mounting clips on the wall. Put a self adhesive clear photo mounting corner at each corner of each photo. Rub it down so it is stuck to the glass well. You want the photos on the back of the glass facing out.

Step 5: Stiffen Photos If Using Larger Prints

I used 8x10 and 11x14 prints for this project. They were too floppy to stay flat against the glass on their own. I decided to add poster board to the back of the photos to stiffen them. If you are using smaller size prints, you can probably skip this step. Some of mine were still bowed a little bit. I may glue on another layer or even stick a piece of foam core behind them.

Cut pieces of poster board about 1/2" smaller than the photos. Spray some glue on the poster board and stick it to the back of the photo. Smooth it out so there are no wrinkles in the photo. Let the glue set the recommended amount of time.

The Loctite stuff I used is basically sprayable rubber cement. You can peel it off and re-set it as long as you don't wait too long.