1. Open your image in Photoshop and create a new layer (CTRL+Shift+N).
2. Select the new layer and pick the Rounded Rectangle Tool (U). Using this tool, create a rectangle around your picture like I did here. You can right-click your rectangle and choose Free Transform Path to better scale and position your rectangle around the edges.
3. Right-click your layer (now named Shape 1) and select Blending Options. On the window that opens up, set the Fill Opacity to 0%.
4. On the same window select Stroke at the bottom. In Position drop-down menu, pick Inside. Set a border size to your liking and pick the color of your border. I chose purple. Press OK when you are happy with the result and you've finished. You can save and export your image.
