Ok, if you were to do what I did, open the images and then crop and make the work space alot bigger. Then copy+ past the two layers or ctrl + J the layers and free transform, right-click Flip Vertical. Bring down that layer so its connected to the top image. Highlight the bottom images, hit add layer mask. Click on the gradient tool(make sure it's Black[L] to white[R]) and
then do the action bottom to top.