Label filter for altered extensions?

I would like to have a label filter, that detects all changes to the JPG extension. I´m quite sure, that it can be done
somehow using Regex, but i have no clues about that matter. Example, the filter would set a specific label color,
when the extension *.jpg123 is detected.

So you want to know how to make a filter which matches *.jpg123?

Name, Match, *.jpg123, [x] Use wildcards.

Not exactly, it should match .jpg***, where * can be any number. It should also work in case there are
only three digits, like *.jpg016, *.jpg8354 etc.

I´ve tried a filter that matches *.jpg????, but that´s not working.

If you want it to match any three or four digits at the end then using a regular expression works best:

.jpg\d{3,4}$

\d means digits, so that's the same as writing:

.jpg[0-9]{3,4}$

Both do the same thing, maybe the 2nd is easier to understand.

Thx, Leo, that works very well. I´m afraid, that Regexes will remain closed books for me,
except for maybe very simple examples.