I have done this in the past but my version of Photoshop is about 20 years old (although I still haven't mastered it!) I had a Quick Look online for you and found this it sounds similar to how I did it (I think!!) maybe it will give them a good idea of what is required.
Creating a triptych in Photoshop is straightforward! A triptych is a single image divided into three panels or three related images displayed side-by-side. Here’s a simple guide:
Step 1: Set Up Your Canvas**
1. **Open Photoshop.**
2. Go to **File > New** to create a new document.
- Set the **width** to three times the width of your desired panel size.
- Set the **height** to match your desired panel height.
- For example, for panels that are 1000 x 1500 pixels, set the canvas size to 3000 x 1500 pixels.
- Ensure the resolution is **300 DPI** for high-quality output.
3. Click **Create.**
Step 2: Add Guidelines for the Panels**
1. Go to **View > Guides > New Guide Layout.**
2. In the popup:
- Set **Columns** to 3.
- Set **Rows** to 1.
- Leave the **Gutter** at 0 unless you want space between the panels.
3. Click **OK.**
- You’ll now see guidelines dividing your canvas into three equal sections.
Step 3: Add Your Images**
1. Drag and drop your images into Photoshop or go to **File > Place Embedded** to add images.
2. Use the **Move Tool (V)** to position each image into one of the sections.
- Resize the images if needed by pressing **Ctrl + T** (Windows) or **Cmd + T** (Mac).
- Hold **Shift** while resizing to maintain proportions.
Step 4: Adjust and Crop Images**
1. Use **Layer Masks** to hide parts of the image that extend beyond a section:
- Select the image layer.
- Click the **Add Layer Mask** icon at the bottom of the Layers panel.
- Use a black brush to paint over areas you want to hide outside the panel.
2. Repeat for each section until the images fit neatly within the guides.
Step 5: Add Borders (Optional)**
1. If you want space between the panels:
- Go to **Image > Canvas Size.**
- Increase the canvas width slightly (e.g., add 100 pixels).
- Use the Paint Bucket Tool to fill the background with a solid color.
Step 6: Save Your Triptych**
1. Go to **File > Save As** and save the project as a **PSD** to preserve layers.
2. To export:
- Go to **File > Export > Export As.**
- Save the file as a **JPEG** or **PNG** for sharing or printing.