How to Auto align and merge images in Photoshop

Open your first image and go to the rectangular marquee tool and select all of the image. Next click command or control C to copy image. Then go to your second image and click command or control V to paste the image. Select both the layers (hold down shift when clicking the layer), then go to edit, auto align layers and choose the top option then click ok. Last add a mask to your top layer, this is done by selecting the gradient tool (make sure its set black to white, the mode is normal and opacity is 100) start furthest away from the object or image in your photo then click and slowly move toward it to reveal the other image.