Cache

This is temporary storage space used by software so that files you need often can be accessed more quickly. It’s typically used for image thumbnails and previews in programs like Adobe Bridge and Lightroom. Sometimes cache files cause problems and must be purged or deleted, sometimes the storage allocation for the cache needs to be made larger in the application preferences to improve performance. Caches and cache files are generally expendable, but they are there for a reason and to speed up performance.