It's a photomontage. Photomontage is the process (and result) of making a composite photograph by cutting and joining a number of other photographs. The composite picture was sometimes photographed so that the final image is converted back into a seamless photographic print. A similar method, although one that does not use film, is realized today through image-editing software. This latter technique is referred to by professionals as "compositing", and in casual usage is often called "photoshopping". ( http://en.wikipedia.org/wiki/Photomontage )
"Reflection" is what Sears Photo calls it--for sales and marketing purposes, but it's still the combination of two photographs (in the sample you've cited). And--as has been indicated in the above definition, this effect can be created using Adobe Photshop. I'll try to explain how I'd do it--in simple terms.
Two photos are involved--one of the baby, and the other of the mother and baby. You combine these two photos into one, using the layers feature of photoshop. Layers allows you to reposition the two photos and adjust the properties of each photo independently. Example--the opacity (transparency) of the the mother-child photo, as well as the color and appearance has been adjusted so that they they appear to be "faded into the background" while the baby photo is pretty much left "as is" (so it's the stronger foreground photo).
After the photo has been worked to your satisfaction, the layers are (permanently) "merged" into one photo, and the changes saved.
That's the simple explanation of the process. It's not a terribly hard process to learn and master. The only requirement is to own a working copy of Adobe Photoshop (or other photo editing software that allows you to create and work with layers).
Hope this helps!