Yes, deleting .nomedia and .thumbnails files on Android is safe. Neither holds anything irreplaceable: .nomedia is a tiny marker that tells the gallery to ignore a folder, and .thumbnails is a cache of preview images Android rebuilds on demand. Remove them and your actual photos, videos, and music stay exactly where they are.

TL;DR

  • .nomedia is an empty marker file that hides a folder's media from the Gallery and music apps.
  • .thumbnails (often in DCIM/.thumbnails) caches small previews so galleries load fast.
  • Both are safe to delete and Android regenerates them as needed.
  • Deleting .nomedia makes that folder's media reappear in your gallery; deleting .thumbnails forces a one-time preview rebuild.
  • Your originals are never touched; only the markers and cached previews change.

What are .nomedia and .thumbnails files?

.nomedia is an empty file with no contents at all. Its mere presence in a folder signals Android's media scanner to skip that folder, so the photos, videos, or audio inside don't show up in the Gallery, Photos, or music apps. Apps use it to keep their assets out of your camera roll.

.thumbnails is a hidden folder, commonly at DCIM/.thumbnails, holding small cached copies of your images and video frames. The gallery shows these previews instead of decoding full-size files every time you scroll, which keeps browsing smooth.

Is it safe to delete them, and what happens?

Yes, both are safe to delete. If you remove a .nomedia file, the media in that folder becomes visible to your gallery again the next time Android's scanner runs. If you add one back, the folder hides again. Nothing about the media files themselves changes.

If you delete the .thumbnails folder, your gallery loses its cached previews and rebuilds them automatically. Expect the gallery to feel slower for the first scroll or two while it regenerates previews, then it returns to normal. This is also why .thumbnails can balloon to hundreds of megabytes over time, and clearing it can genuinely free space. For a step-by-step on that, see how to delete hidden thumbnails on Android.

What Android does natively, and where it stops

Android's media scanner manages both automatically. It honors .nomedia whenever it indexes storage, and it recreates thumbnail caches whenever an app requests a preview that isn't already cached. You generally never have to create these files yourself.

Where it stops: Android rebuilds .thumbnails but rarely prunes it aggressively, so the cache can grow large and outlive the photos it was built from. And there's no user-facing toggle to bulk-manage .nomedia flags across folders; that behavior is decided by individual apps. So clearing an oversized thumbnail cache or surfacing hidden media is something you often end up doing by hand.

What deleting them cannot do, and what to leave alone

Deleting these files cannot recover or repair lost photos. They're markers and caches, not backups; if an original is gone, removing .thumbnails won't bring it back (though a leftover thumbnail is sometimes the last surviving preview of a deleted image, so don't assume .thumbnails is pure junk).

Leave unrelated hidden files alone. Folders for games and large apps may store data you don't want to touch, such as Android OBB files, which are expansion assets, not throwaway cache. Stick to .nomedia and .thumbnails when you mean to clean media clutter.

FAQ

Yes. Once you remove a .nomedia file from a folder, Android's media scanner stops skipping it, and the photos or videos inside reappear in your gallery on the next scan. The files were never hidden on disk, only excluded from the gallery view.

Does deleting .thumbnails delete my actual photos?

No. The .thumbnails folder contains only small cached previews. Your full-resolution photos and videos live elsewhere and are untouched. After you clear it, the gallery simply rebuilds previews the next time you browse.

Why does .thumbnails get so big?

Android keeps caching previews for new and old media without aggressively cleaning up, so the folder grows over time and can reach hundreds of megabytes. Clearing it reclaims that space; the cache then rebuilds only the previews you actually view.

Thumbnail caches are just one corner of the clutter Android piles up. The Cleanor app helps you clear caches, duplicates, and old downloads so your storage goes back to the files that matter.