Compatible XF Versions:
XenForo Media Gallery 1.0.0 or above
This simple add-on has a very specific use case, which likely won't apply for most people.
The use case being that if you ever manually update the values in the xengallery_field_value table, because the custom field values are cached.
This add-on adds a rebuilder at Admin CP > Applications > Gallery Rebuilds (at the bottom) which when executed will go through all of your media items and rebuild the custom field cache for each media item.
Add-on XFMG Custom Field Cache Rebuild 1.0.0
Rebuilds XFMG custom field cache for each media item