Is there a program to edit large images piece by piece?

Question

Graphic arts

Good afternoon.
Let's say there is a large (1,000,000 x 1,000,000 px) image that you really want to edit. It does not fit into regular editors. Is there an editor that allows you to edit image fragments?
The point is not even that there is one giant image. Most likely it will still be stored in separate parts. The main difficulty is how to edit the borders of these parts.
If closer to the real application - a map of the world. It is stored in tile sets for different scales. Editing tiles individually is quite laborious. We need the ability to load a set of tiles (let's say 8x8 tiles) as one image, edit it, then break it back into fragments. In principle, it is possible to implement this with various crutches, but what if there is a special program?

Answer 1

Well, for example, Photoshop in the past era of a small amount of RAM loaded the image in parts and has not forgotten how to do this until now.
I mean that this is not an achievement for a normal graphics editor. Another thing is that not all editors can do 1 million by 1 million pixels.

Answer 2

It is hard to believe that large images are entirely stored and displayed.
Rather, it consists of gluing together small ones ..
\\\
And so Photoshop solves most of the problems.
At least I have 30,000 x 30,000 seems to be mastering =)