Resize with empty border for safe zone

[edgarrames]

Hello folks,
I am hoping to find some help resizing my images so that the entire image fits within a safe zone, leaving an empty space around the border.
They are starting at 1024x1024 pixels, dpi 96. I want the final image to be 939x939 with a dpi of 301. This makes it a 3.125 inch size. But I want the whole image to fit within a 2.9 inch safe zone, and to fill the rest with empty/transparent.
Is this possible? If it takes multiple steps, that's fine.
I've tried resizing them smaller, and then resizing them back up with 'pad' but it doesn't seem to be working. It just ends up making the image the whole size.
Any help would be super appreciated.

[edgarrames]

figured a work around method , using other gimp tools to make a border