Opening THUMB Files

The THUMB file type is primarily associated with Photoshop.

THUMB	File extension: THUMB
	File type:	thumbnail image file

What is a THUMB file?

THUMB files mostly belong to Photoshop. The THUMB file is a small image file used to store a quick preview of a larger image. These files act as hidden caches that let software show a preview without loading the full-resolution file.

JPEG thumbnails: Many THUMB files use the JPG format. Programs like Photoshop and image managers such as XnViewMP generate these for fast display.

PNG caches: Some systems, for example Apple Photos, store thumbnails in the PNG format. You can see this in cache systems referenced by the iCloud Photos service.

Android thumbnails: A few THUMB files act as caches on Android, speeding up image browsing.

FilExt.com note: These files are not intended as the main image but serve to improve performance and make it faster to preview images. To view a THUMB file, you can open it with common image viewing software or rename the extension to .jpg or .png if necessary.

How to open THUMB files

You need a suitable software like Photoshop to open a THUMB file. Without proper software you will receive a Windows message "How do you want to open this file?" or "Windows cannot open this file" or a similar Mac/iPhone/Android alert. If you cannot open your THUMB file correctly, try to right-click or long-press the file. Then click "Open with" and choose an application. You can also display a THUMB file directly in the browser:. Just drag the file onto this browser window and drop it.

Online THUMB Text Viewer

Choose your .thumb file to analyze

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Online File Viewer

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THUMB format details:

Each file has a definite file format, that is, how the stored data is arranged in the file. The initial characters of a file are called signature, sometimes also referred to as "magic bytes". The signature can be used to infer the file format. Nonetheless, different programs can utilize the same file extension to represent distinct file formats. Double-clicking on the file often results in an error when opening. So a detailed analysis of a file is vital in order to determine the format and the associated program. Below you will find our evaluation of the THUMB files:

The THUMB extension is very commonly used. This THUMB file itself is among the most popular common file types and is primarily used by a single program. However, the following two file formats are common:

• 80% of all THUMB files are using the well-known JFIF file format to store the data. JFIF is short for JPEG File Interchange Format. It is a bitmap graphic that uses JPEG compression. If you open these files in a text editor, you will see only illegible characters. The file size is in the range of 1 KB to 63 KB. The file type is relatively new. The keywords JFIF are typical for these files. Files like these have the following tags: null, brunafiguei and snapchat.
• 3% of all THUMB files use the popular PNG file format. PNG is short for Portable Network Graphics. It is a high-quality raster image file that supports lossless data compression. These are binary files, so they do not contain words or text. The files are often between 4 KB and 180 KB in size. Several words can almost always be found in the files, e.g. IHDR, IDATx, sBIT and sRGB. An example of a file name is DJI_20180601.mp4.thumb. Files like these are about drawing.

All other THUMB files (17%) have no consistent format, the following 5 formats can be found: SQL. These files are often connected to screenshot, gallery, cimage, item, stamp or prop. If you want to find out what your THUMB file contains, drag and drop it onto this page.