One of my 'disagreements' with using pre-made scripts. Useful for many things but get to know the built-in Gimp tools first.
Might not be as good-as but it will be
your own workSuggestion.
1. The background can be a rectangular selection with rounded corners. Select -> Rounded Rectangle Fill with color / pattern / gradient (whatever you want) and apply Filters -> Decor -> Apply Bevel
https://i.imgur.com/LlCuPyJ.jpg2. Now you can add the image, and this can be color or desaturated. Whichever type duplicate and if necessary desaturate and give it a small blur Filters -> Blur -> Gaussian Blur
That is the bump map. https://i.imgur.com/Dlyl3yG.jpg3. Back to the original image layer, Apply Filters -> Map -> Bump Map using the blurred layer (now with visibility off) as the Aux Input. Play around with the parameters.
https://i.imgur.com/8Xhc1Wd.jpg4. A small point but consider direction of light. If necessary flip that beveled rectangle.
https://i.imgur.com/yUdFs24.jpg5. Need it all one colour. Layer -> New from Visible. Apply Colors -> Colorize to that layer. (plenty other ways as well)
https://i.imgur.com/nojGXAx.jpgEasy, but bump-mapping is used in so many processes, when you have a spare 5 minutes, practice using it.