Hi Sven.
I have recently noticed that pictures thumbanails in my slidegalleries take a while to be uploaded in the page, and appear. You can check here: https://www.waterwind.it/new/en/windsurfing/reports-and-photos/photos-shop/events.html
Once images are cached, there is no problem. But before caching, they take lots of time to appear.
I didn't change any settings, but only updated the extension constantly.
What can have happened?
Thanks