I want to create an image what a web page looks like,
e.g. create a small thumbnail of the html + images.
it does not have to be perfect (e.g. flash /javascript rendering).
I will call use the code on linux, ideally would be some java library, but a command line tool would be cool as well.
any ideas?
Try CutyCapt, a command-line utility. It uses Webkit for rendering and outputs in various formats (SVG, PNG, etc.).