Here is everything you actually need to know about Thumbdata files and how to safely view them online. If you’ve ever used an Android phone (especially versions 4.0 to 9.0), the Gallery app created a hidden database of every photo thumbnail it generated. That database is the .thumbdata file.

Don’t risk uploading private photo thumbnails to a random website. Download a reputable open-source desktop viewer instead.

No simple drag-and-drop web tool will magically show you a clean slideshow.

What Is a Thumbdata File? How to View It Online (Without Installing Sketchy Software)