I have two images that were taken at the exact same spot by at a different time. I want to make a side by side comparison image to show the differences of a zoomed in crop of the image. How do I do this in photoshop? How do I make sure that the two crop sizes are the same and at the exact pixel location between the two images?
The easiest way would be to position the two images above each other in separate layers, set the upper layer to 50% transparency. You can then manually align the layers and crop the images to a specific size. First save the image with the lower layer visible, then the upper.
There's probably a better way to do it, but if you need to do it only once, it's probably not worth putting effort into.