20 MB GIF sample

A GIF file of exactly 20,971,520 bytes. It is a valid Graphics Interchange Format file, generated by this site. Compare its checksum and test it with the parser used by your application. Use it wherever you need a 20 MB sample, test or dummy GIF file.

sample-gif-20mb.gif

20 MB20,971,520 bytes

Download 20 MB GIF

Created in your browser in a few seconds, then checked against the SHA-256 checksum. No sign-up.

Type: image/gif
SHA-256: 28714c72c2e401991ebabdd33307bebdfdd28d79820d82194edb24f4b2f11a79
Delivery: Created in your browser from static generator assets (how it works).

What is in this file

A looping 480 × 360 animation of 238 LZW-compressed frames; the last frame repaints only the top of the canvas. 407 bytes of GIF comment extension bring the file to the exact size.

Dimensions	480 × 360 px
Frames	238
Frame delay	80 ms
Loop	Forever
Colours	256 (global colour table)
Version	GIF89a

First bytes of the file

The first 64 bytes of sample-gif-20mb.gif as a hex dump: offset, bytes, then the same bytes as text. The GIF signature is 47 49 46 38 39 61.

00000000  47 49 46 38 39 61 e0 01  68 01 f7 00 00 00 00 00 |GIF89a..h.......|
00000010  00 00 33 00 00 66 00 00  99 00 00 cc 00 00 ff 00 |..3..f..........|
00000020  33 00 00 33 33 00 33 66  00 33 99 00 33 cc 00 33 |3..33.3f.3..3..3|
00000030  ff 00 66 00 00 66 33 00  66 66 00 66 99 00 66 cc |..f..f3.ff.f..f.|

Preview

Creates the file in your browser and shows it here. Nothing large is downloaded from our server.

Where 20 MB matters

A 20,971,520-byte file: right at the default attachment limit of Outlook, and just under the 25 MB ceilings of Gmail and GitHub web uploads. These are the default limits a file of this size is useful for testing:

System	Limit	Note
Microsoft Outlook	20 MB of attachments by default for internet mail accounts	This file is right at the limit; add a second attachment and it is exceeded.
Gmail	25 MB per message	Under the limit, although email encoding adds about a third in transit.
GitHub web uploads	25 MiB per file added through the browser	Accepted. Pushing with Git allows larger files.
Cloudflare Pages assets	25 MiB per file	The largest round size that can be served as a static asset.
Amazon API Gateway	10 MB payload	Rejected; the upload has to go directly to object storage.
ASP.NET Core (Kestrel)	About 28.6 MB request body by default	Accepted with room for the multipart overhead.

All 20 MB sample files

Use this file for

Testing image resizing and memory use
Checking frame-count and duration limits
Testing avatar and reaction uploads

Testing notes for GIF

Many resizing libraries silently keep only the first frame of an animated GIF.
Animated GIFs are large for what they show; a few seconds can reach several megabytes, so they hit size limits early.

GIF format reference

Technical details

File name	sample-gif-20mb.gif
Format	GIF (Graphics Interchange Format)
Extension	.gif
MIME type	image/gif
Size	20,971,520 bytes (20 MB)
Kind	Binary
Signature	47 49 46 38 39 61
SHA-256	28714c72c2e401991ebabdd33307bebdfdd28d79820d82194edb24f4b2f11a79
Created	2026-10-23
Validation	See the listed size and SHA-256. Small downloads are checked in the browser; verify streamed downloads manually. A hash match does not prove parser compatibility.
Preview	Available on this page
Source	Generated in your browser by this site's generator; not copied from elsewhere
Licence	Free to use, modify and redistribute (terms)
Category	Images

Check the stated structure and checksum against your application requirements. As with any download, scan the file with your own security tools before opening it. How files are made and checked

Verify your copy

This file is created in your browser, so it has no direct URL for curl or wget. The generator is designed to produce reproducible bytes. After saving, compare the checksum with the SHA-256 value above.

sha256sum sample-gif-20mb.gif     # Linux
shasum -a 256 sample-gif-20mb.gif # macOS

On Windows, run Get-FileHash sample-gif-20mb.gif -Algorithm SHA256 in PowerShell. For scripts and pipelines, save the file once and keep your own copy.

Related files

Questions about this file

Is this file exactly 20 MB?: Yes. It is 20,971,520 bytes, which is 20 MB in the binary units that operating systems and server limits use (1 KB = 1,024 bytes).
What is inside the 20 MB GIF file?: A looping 480 × 360 animation of 238 LZW-compressed frames; the last frame repaints only the top of the canvas. 407 bytes of GIF comment extension bring the file to the exact size.
Are the sample GIFs animated?: Yes. They loop forever at about 12 frames per second. The frame count for each size is shown on its download page.

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