But, sometimes, no matter how good your intentions, this process can throw a curveball at you. Namely, if the images you’re opening as layers are not all exactly the same size, they won’t be exactly the same size in the Photoshop document. If the images are from the same camera, you might think it’s no problem. But, if you’ve cropped any of the images in Lightroom’s Develop Module in order to, for instance, make the head sizes in a series of portraits about the same, then when you open the files in Photoshop the program will essentially undo all that cropping because the layers will be built on the actual pixel sizes of the images. So, if you cropped from an image that was 2000 x 3000 pixels down to 1600 x 2400 pixels, unless every image selected was cropped to the exact same size, they’ll open as different sized layers in a document sized to accommodate the largest file.
So, how do you work around that? Simple. You first export the images to a folder on your desktop, with all of the images set to be resized to fit a particular dimension—say 1600 x 2400 pixels. Lightroom will export these images as JPEGs or TIFFs or whatever format you’d like to use, and all of them will now be the same pixel size (1600 x 2400 pixels), which will mean the crops you made have had their desired effect. From here, simply open Photoshop and look for the Scripts heading near the bottom of Photoshop’s File menu.
Then, click on Load Files into Stack to bring up the Load Layers popup menu that allows you to select the files you’d like to make layers in a single document, either by selecting the folder placed on your desktop or by using the Browse button to open that folder and select the individual images you’d like to use.
Then, click Okay and watch Photoshop run, placing all of the selected images into a new multi-layered image file—with all layers exactly the same size—that’s open and ready to be worked on in Photoshop.