Dummy JPG File Generator
Every dummy JPG file is a valid JPEG at the width and height you pick, padded to the exact byte size.
Sample JPG files, ready to download:
One click, exact size (1 KB = 1,024 bytes), default options, built in your browser.
A dummy JPG file is a real JPEG image made for testing, and it opens in any browser or photo viewer. Download one free at the exact size you need, from 768 Bytes to 50 MB. Choose the width and height under Options (800 x 500 by default) and the size, then use it to test photo uploads, avatar crops, re-compression and attachment limits. It is a generated graphic, not somebody's holiday photo, so you can attach it to a bug report without a second thought. For lossless pixels, use a dummy PNG file.
How we check it: every generated file must be exactly the size you set and pass a decode in headless Microsoft Edge at the chosen width and height, plus our own JPEG marker checks; the last browser run on 21 October 2026 passed 520 of 520 cases (how the files are made and checked).
What is inside a dummy JPG file
The file is a standard JPEG with comment segments added to reach your size (how we build and check these files):
- A JPEG encoded by your browser at quality 0.92, at exactly the width and height you chose.
- The same picture as the other dummy images: a dark slate card, a faint grid, a blue glow and a badge with the file name and the dimensions.
- The extra bytes are JPEG comment segments (COM, marker FF FE) just before the end-of-image marker. One segment holds up to 65,533 bytes, so a big file carries many of them. Decoders read past comments, so the picture does not change.
- No EXIF block: no camera model, no GPS position, no orientation flag. If your code reads EXIF, this file tests the "no EXIF" path.
- The smallest possible file depends on the dimensions and your browser (roughly 25 to 30 KB at the default size); the tool shows the exact minimum if you ask for less.
What a dummy JPG file is used for
Photo upload forms
Check profile photos, listing images and document scans against your size limit with a JPEG that is exactly on the boundary.
Avatar and crop tools
Try a very wide, a very tall and a tiny image and confirm the crop, preview and saved result all look right.
Re-encoding pipelines
Find out whether your pipeline re-saves uploads. If it does, the comment padding disappears and the stored file is far smaller than the upload.
Email and chat attachments
Send JPEGs of a known size through mail servers, chat apps and ticket systems to see where they get rejected or shrunk.
How to test a photo upload limit
Make three files: one byte under the limit, one exactly at it and one byte over. With the unit set to Bytes, a 10 MB limit means 10485759, 10485760 and 10485761. The first two should upload. The third should fail with a clear message, not a timeout or a blank page.
Browsers send both .jpg and .jpeg files as image/jpeg. Upload filters that check the extension sometimes list only one of the two, so test both: pick "JPEG (.jpeg)" in the format list to get the other extension.
| Limit | Size | Notes |
|---|---|---|
| nginx client_max_body_size (default) | 1 MB 1,048,576 B | Requests with a larger body get HTTP 413. |
| PHP upload_max_filesize (default) | 2 MB 2,097,152 B | Also capped by post_max_size, so raise both. |
| AWS Lambda synchronous invocation payload | 6 MB 6,291,456 B | Applies to request and response. |
| Amazon API Gateway REST API payload | 10 MB 10,485,760 B | Hard quota for REST APIs. |
| Outlook default attachment limit (Exchange accounts) | 10 MB 10,485,760 B | Administrators can change it. |
| Outlook attachment limit (internet accounts) | 20 MB 20,971,520 B | Per Microsoft Outlook guidance. |
| Gmail message size limit | 25 MB 26,214,400 B | Attachments grow about a third when encoded, so a 20 MB file can already be too big. |
JPG or JPEG: is there a difference?
No. .jpg and .jpeg are the same format with the same MIME type. The three-letter version comes from old Windows file systems that allowed only three characters after the dot, and it stuck. The file you download here is identical apart from the extension.
Why the padding survives some tools and not others
Image viewers ignore JPEG comments, but many upload pipelines decode and re-encode every image. When that happens the comments are dropped and a 10 MB dummy JPG comes out at a few dozen kilobytes. That is not a bug in the file; it tells you your pipeline re-encodes. If you need the original bytes stored, compare the stored size with the uploaded one.
JPG file details
- Extension
- JPG .jpg
- MIME type
- image/jpeg
- Smallest size
- 768 Bytes
- Largest size
- 50 MB
- Contents
- JPEG image at the width and height you choose (default 800 x 500); extra size is COM comment padding before the end marker
Dummy JPG file FAQ
Is the dummy JPG a real photo?
It is a real JPEG image but not a photograph: a simple generated graphic with the file name and dimensions on it. Browsers decode it at the width and height you chose, which we check in Microsoft Edge along with the JPEG marker structure.
What are the disadvantages of JPEG?
JPEG is lossy, so every save throws away a little detail, and it has no transparency. For tests that need exact pixels, use PNG instead.
Can I set the width and height?
Yes. Open Options and enter the width and height in pixels, from 1 to 8,192; the default is 800 x 500. The size you set stays exact, and if it is too small for the dimensions the tool tells you the minimum.
How is the exact file size reached?
With JPEG comment segments placed before the end-of-image marker. Viewers skip them, so the picture is unchanged whatever the file size.
Does the dummy JPG contain EXIF data?
No. There is no EXIF block, so no camera details, no location and no orientation tag.
How large can a dummy JPG file be?
Up to 50 MB, at up to 8,192 x 8,192 pixels. Very large dimensions may fail on phones; a desktop browser handles them.
Is my image uploaded?
No. The JPEG is created in your browser and never leaves your device.