Here is how you can import your photos through Adobe Lightroom. If you do not use Lightroom, you can skip this part. If you use Lightroom, this is a great way of working with HDR photos. Select the three exposure, right click, then choose Edit In > Open as Layers in Photoshop. The new tone mapped image will appear as a new image in Lightroom when you’re done. You can stack the four photos (3 exposures + 1 tone mapped image) for better organization.
With Photoshop CS3 or newer, you can load images into a document as layers easily with the Load Layers script. Choose File > Scripts > Load Files into Stack. Browse for the three images then click OK. Enable the “Attempt to Automatically Align Source Images” option. With this option enabled, Photoshop will automatically align the layers to compensate for slight movements. This works almost all the time but in case it doesn’t, you can disable it. Because you’ve already aligned your layers, skip the next step (Step 2 – Aligning the layers).

Open all three images into Photoshop. Tile the images so that you can see all three. While holding the Shift key on your keyboard, drag the layer of one document to another. Repeat this with the third image. One of the images should have three layers. Depending on the version of your Photoshop, you may have to reposition the layers so that they look aligned. You can close the other two images.
