How to create a border around an image for projection
If the edges of your image are very dark, you may want to create a thin line around the image to separate it from the black background that appears during projection. Alternately, you may want to create a "mat" similar to those used for prints.
Adding a border in Photoshop CC/CS
Note: With this method, a border is added around your existing image, so you don’t have to worry about any of the image edge being covered by the border. However, the border should be added before you resize your image. Otherwise, if you create a wide border, it will be counted as part of your image size and your image may be too big to upload.
In Photoshop CC/CS
1. In the taskbar at the top of the screen, click on Image and then Canvas Size in the dropdown menu. Click the Relative box.
2. Make sure the anchor point (the round dot in the graphic) is in the center and then enter a number in the Width and Length boxes. If you want to make a mat around the image, you can designate the number of inches you prefer. If you just want to make a thin border, you’ll want to designate the number of pixels (3-5 is about right.)
3. Select White from the Canvas extension color. Or, if you’d like a different color, click on the arrows to get a dropdown menu. Click on Other to bring up the Color Picker. You can now select a light color of your choice. Suggestion#1: Choose a color that complements one of the colors in your image. Suggestion #2: Keep your borders very narrow--just enough to outline the photo and separate it from the dark background when shown on screen. (Wide borders can distract from the photo and thereby result in a lower score.)
4. Click OK and proceed to the resizing steps above.
In Photoshop Elements
1. On the taskbar, go to Edit workspace and then to Image > Resize > Canvas Size.
2. Follow the steps under CC/CS above.
Adding a border in Apple Photo:
Go to Apple Support at: https://support.apple.com/guide/preview/resize-rotate-or-flip-an-image-prvw2015/mac
Adding a border in Lightroom:
Lightroom doesn’t have a good system for adding a border to an image, so if you have access to Photoshop, you should use it.
If you must use Lightroom, go to https://laurashoe.com/2013/10/11/how-to-create-photo-borders-in-lightroom for the best instructions. You should note, however, that Lightroom will create a border that covers pixels at the edge of your image. That’s something to keep in mind if you choose to add a border wider than a few pixels. This method also produces a border with rounded corners, which you may not like.
After you’ve added a border in the Develop module, go back to the Library module and click on Export. In the dialog box that appears, size the image as described above.