.tdb

Android devices may generate a SThumbDB.tdb file on an SD card when it is inserted into a phone or tablet. The SThumbDB.tdb files stores a cache of thumbnail images that represent the full size images saved on the card. It is similar to the Thumbs.db file generated on Windows computers.

Caching small versions of the images provides faster browsing of the images on the card and can dramatically improve performance if there are hundreds or thousands of images stored on a single card. Since the TDB file is used by the Android OS, it is not meant to opened or edited.