SImGallery takes 10 mins to load

I have purchase SimGallery 3 times now and never managed to get it to work successfully with Jomsocial. Last year we switched to Easysocial, so I thought maybe its time to give SimGallery another chance. This time it worked fine except that the migration from Easysocial never completed successfully (only about 15% of the albums/photos were converted).

Testing the new version, now SimGallery takes up to 10 mins to load!!!!!
And most of the photo's are still broken.
The max page load on any other page is 20 seconds.
We have about 40 000 photos on the site.