Go here to down the template I use. Here are some quick steps for those of you who are familiar with Photoshop.

1. download file and open in photoshop
2. open image you want to put in square
3. add image to template file by dragging it in using the move tool
4. look over at the layers palate and move the image just above the square you want it to go in.
5. with the image layer active hit alt+ctrl G (opt+cmd G) or go to layers menu and click create clipping mask. This will clip your photo into the square.
6. if the image is too big, most likely it will be unless you changed size before hand, click ctrl or cmd T and while holding the shift key down move the bounding box around the image at the corner to shrink the image down to the size you want. As long as you keep the shift key down while moving, the image will keep it’s original dimensions.
7. When you get it the size you want hit return or enter.
8. Use the move tool to move image inside the square to your desired position.

repeat steps 2-8 for the rest of the images.

If you need a visual I think Michelle’s Marc did a great job explaining it here. Please don’t hesitate to ask if you have a question. Thanks.