Thanks for the quick reply and sorry for the wrong category. I'm a newbie in this forum.
Here is the link to my exported project: https://drive.google.com/file/d/1lKAf9JS7baeiy0SDs837Uok6jAZpqPyp/view?usp=sharing
I took the JavaScript-Code from this post: Load image as costume from URL - #2 by jens