The PhotoEditor seems to work fine. However, when I choose a picture from the Editing list by clicking on it, my computer produces a very loud and annoying sound, a bip. The same thing happens, when I choose different effects, balloons or frames, by clicking on one of them. This sound does not come via my speakers – it is still there, when I mute the sound.

Hello, tino.
New ALSee is coming under way very shortly.
Although, the problems you are facing now shouldn't be happening. Let me take a look and search under the forum to see if any similar issues have been reported before.
Best Regards,
AHyun