Creativit saves the thumbnails of your already-viewed items in the dedicated app’s caches folder on your device in order to load them quicker next time you view them.
In order to clear the cache, please go to the settings of the app, and under the ‘Integrations’ section, tap on the ‘Clear Cache’ button. This will clear all of the current cache, but please note that next time you will go to any of your folders or tags to view the items, the app will cache the thumbnails of these items again.