How to resize an image so it's content would stay centered?

[rich2005]

I think for the scaling 512x512 (or any WxH) > 1080x1920

1) scale the to the height. Image -> Scale
2) Set the canvas size to 1080x1920 Image -> Canvas Size Center it / Set the fill type

example: https://i.imgur.com/jiAApIW.mp4

I did not quite get your description for the zoom something like Krikors animation or maybe this

https://i.imgur.com/qkkUSoe.mp4

edit: nearly forgot. The image is in Indexed Mode change it to RGB. Image -> Mode -> RGB