page6
First image: it's smaller than the page. Selecting both, image and shape and performing Right click → Shapes → substract (4th Form function) you'll obtain the expected result. 5.3.6.1 ok
Second image: it's the same than before, but it was enlarged
Now, selecting both, enlarged image and shape and doing Right click → Shapes → substract (4th Form function) you'll obtain the expected result. 5.3.6.1 ok
Third image: originally larger than the page. Selecting both, picture and shape and doing Right click → Shapes → substract (4th Form function, in german substrahieren) you'll obtain the expected result. 5.3.6.1 ok