Compress different parts of a pix by different amounts?

I don't know the proper terms, but here's the idea.
Take a big pix at high resolution (eg spectators at a football game).
Use a combination of pixel scaling and compression to
get a highly compressed picture, small file size, picture 1.
Print picture 1.
Print the original picture.
Take scissors and cut out small parts of the high resolution
(eg a face)
pix and glue them on Picture 1 in the right places.

Wanna do that digitally.

I want small file size. I want the big picture for context.
I want high resolution in a few small parts of the picture.
I'd like to render the picture on a windows PC without extra stuff.
Would be nice to be able to put the pix on a website and have
a standard PC browser render it correctly. I want it freeware.

Ideas?
Thanks, mike

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