Thank you for your answer. Unfortunately, there was a little misunderstanding.
When I insert an image into the "filmstrip", it does not fill its place 100%. There remains a border, a background, which I can design, but which I don't want.
I can prevent this edge by stretching the image. However, I lose parts of the image at the top and bottom.
Is there a possibility to insert the image in full format without losing parts of the image, or can I adjust the "filmstrip" in such a way that the image remains in its proportions in full format?
Please excuse me if I express myself in a complicated way, English is not my native language.