robi, we have checked the issue with the photos
the problem is that the photo cannot be copied from ow_userfiles/plugins/base/attachments folder
usually that happens due to url_fopen being OFF, but in your case it is ON, which means there's some other security setting which blocks that photo moving. You will need to contact your hosting provider to investigate this issue.
Here's the error:
copy(http://test.motospace.de/ow_userfiles/plugins/base/attachments/556c16a457e2a_cdbef6bc80297f747611516c446fd8fe.jpg): failed to open stream: Connection refusedFile:/home/motospace_test/public_html/ow_plugins/photo/classes/event_handler.phpLine:946