JPG File is not allowed

since hours I try to convert a jpg. file in a H5P format and it would not work. The description about this program is mostly about to convert a video file, but not to convert a jpg. file.. I saw, that many other users have the same problem, but no solution, that works! I want to create a course presentation with my own pictures (in a small size!) like the attachement for example. I think, this program does not work properly.