It seems to me that you have used coordinates of the thumbnailed image. But you
has to use them from the original size. Try this:

<imagemap>
Image:Rodenkirchen_Stadtteil_Zollstock.png|thumb|Doh litt Zollshtogg_en[[Zweijte
Stadtbezirrek (Kölle)|singem Stadtbezirrek]]
poly 96 19 37 160 88 191 113 158 102 158 113 107 139 105 118 42 96 16
[[Zollshtock (Veedel)|Dat Veedel Zollshtogg_en Kölle]]
</imagemap>

I had entered a series of coordinates, each being a comma
separated pair.

Thank you for pointing me to my error.

Sorry, I am unable to obtain any useful results. The numbers
you give (though they work describing a polygon in parts
similar to the wanted one, only for the full image, not the
thumbnail) bear no relationship of any type to the pixel
counts displayed by graphics program.

Trying to define and add polygons for the other areas spoils
eveything completely. Clickable areas shrink to line-shape.

I assume some strange measurement being used which is not
pixels. Documenation @ http://www.mediawiki.org/wiki/
Extension:ImageMap does not tell how measurements are made.

[[de:Benutzer:Raymond/imagemap 8923]] works for me as expected (with exception
of thumb title, but this is another bug?!)

It does not work for me.

1. There is no way, to determine which figures are to be noted

as coordinates.
1.1. Documantation does not describe which units are to be
used.
1.2. Obviously it is not pixels.
1.3. Can you explain @ http://www.mediawiki.org/wiki/ how to
get the figures?

2. When the image is scaled, clickable areas are scaled

differently.

This is not working, at least not with Opera 9.01

Example in comment #4 works just fine in Opera 9.02.

Coordinates are pixels in the full-size source image.