>>1458736Make a big new file, big enough to fit your images (New -> File)
Drag the two images, pick "Add layers"
Grab the image you want to see below and keep pressing the down arrow key (you can use the scroll wheel if you're zoomed in, you can also move it every 10px with ctrl+arrow key without pressing it)
Then pick "Move selection", grab some the upper-end points and drag it to the top
Image -> Crop selection
