I'm going to take you step by step through the process I use to create a composite photo. Since Photoshop Elements is my software of choice for these sorts of things, that's what I'm going to be using. In Part 1 of this series I discussed ways to obtain "now" and "then" photos. Assuming you have done that, the next step is to scan them into your computer so we can work with digital images. In Part 2 I discussed a number of software programs that offer the features you'll need to create your composite image. All that's left now is to put it all together. Let's get started...
First you'll need to launch your software and open the two images you want to use. Drag and drop the "then" photo on to the "now" photo. You should end up with each photo on a separate layer in one file. Save your file under a different name than either of your original photos. Here you can see the "then" photo (layer 1) on top of the "now" (background) photo.
For reference, here are the two photos I started with and my final composite photograph.
Melancholy Too, and add this composite image to it. It will give me a complete set of pictures of my grandparent's neighborhood :-)
Creating a Composite Photo, Part 1
Creating a Composite Photo, Part 2