Color(s( transformation and making pixels of given color(s) transparent

This message is also being sent to info@actualtools.com that make products
like:
'Actual transparent windows' for Windows.

Would like to suggest new feature.
You could set all pixels of a colour to be displayed in another colour.
Also instead of choosing another colour you could choose for them to become
transparent.
You would have that in a raw text file with extension .txt: each line
saying which colour-pixels

would go into other colour(or become tranparent).

Like this

#FF0000,#FF0011,#FF0022 : #00FF00;
#FF0011..#FF0099 : #02FF02;
#FF33FF : #transparent

and so on...

each line would have a set of colour(s) followed by a colon and the
transformation colour.
The ".." would mean all contiguous colours between the two.

It would be extremly useful and powerful.

#black&gray : #FF0000;
#greens : #00f200;
#white : #transparent;




simple?
It would be nice browsers had a place to upload such a file in the settings.
The values are nonsense, is just to give an idea.