Everything seems to work as intended, except for the image showing.
The test.txt is indeed showing the base64 string, but as empty image.
If i go to your testpage
and press 'save rect' and then show,
i get http://www.liebhard.eu/c2/c2i/1.2/c2i.png
which is an empty image with dimensions 208x160
I'm using Chrome 18.0.1025.142 medit: Mozilla Firefox 10.0.2 doesn't give this problem, everything working as expected on that.
same for Firefox 11.0, working perfectWishy2012-04-04 17:45:53