How to make a picture square?

Question

GIMP

It seems like a simple thing, I looked at a bunch of basic videos, but I haven’t found the answer yet and I couldn’t do it by typing. There is a logo - it is rectangular, let's say 400x200. I need the picture to become square 400x400, but the proportions of the logo should not naturally change. That is, how to add transparent space above and below. I created a transparent 400x400 image in Gimp, placed a logo on it (I did Align vertically in the center). In Gimp itself, it looks like it should. When I save as png, the size is still 400x200. Maybe I need to do some Merge layers, I don’t know.

When exporting to png, a window appears with different checkboxes, maybe you need to set something there? There is something about transparency and background.

Answer 1

Image -> Canvas Size:
Change Values:
Wow: