Often working for the world of catalogs in the furniture sector, we need to work with the full frame photographic sensor ratio of 1:5, but at the same time be able to visualize in real time what the image will look like when once cut and also where the center of the page will be. An image crop function that makes the portion that is not of interest opaque would be useful and perhaps a tool such as Photoshop rulers both in pixels and cm. I created an example image.
https://i.imgur.com/Ee8Umsp.jpeg