by 'frame', but I would just open my favored image editor, enlarge the canvas, and then add in all the images I want to include.

So specifically I would use Windows MSPaint, which is installed on all Windows OS machines by default. If you are using some other OS, then use the default image editor that your OS uses.

I would open all 4 images using MSPaint. That means 4 different MSPaint windows. I would then open a blank MSPaint window and enlarge the blank canvas.

Then, one at a time, I would copy each of the 4 images, then Paste each into the blank canvas window.

Save the new image and done.