Original & Result:

To see the FULL size result, click HERE.

Step One: Open Photofiltre and the image you wish use.

Step Two: Dupilicate your image by pressing CRTL + U or go to Image then Duplicate. [Example HERE.]

Step Three: With the Duplicate, go to Image then Flip Horizontal. [Example HERE.]

Step Four: Next, right-click and Copy the flipped, duplicate. [Example HERE.]

Step Five: Then, return to the original image, unflipped image, and go to Edit, Paste Special, then Assemble. [Example HERE.]

Step Six: Finally, a pop-up should appear. Set the settings to RIGHT like mine: HERE.

You are now done and should have a similar image to the result above.