Thumbnails in gallery not resized

Good work, but some problems with su_custom_gallery. Place this code:
[su_custom_gallery source="media: 12858,12859,12860,12861,12862,12863,12864" limit="-1" link="image" width="200" height="200" title="never"]
But size of thumbnails not resize accordingly.
How to clear cache and regenerate thumbnails?

The page I need help with: [log in to see the link]