Before adding a header image, i downloaded the one on the Events demo. It was 2560x838 pixels. Then i added a header image of the same size. But i cant see the complete image (which is required) but just the middle of it. In this way, only some part of the image is focused/enlarged and the rest cant be seen as if it is too large:
http://itef.kalemkultur.com/. But if i resize it and put a smaller image then the image startts to repeat itself. So what is the right size to see the image properly?