Download 3 MB JPG image for testing
Preview the image and test your image-upload limit. The preset is 3 MiB (3,145,728 bytes); choose MB for decimal megabytes.
1 MB = 1,000,000 B · 1 MiB = 1,048,576 B
Advanced: test an upload limit
Enter the byte limit above, then choose one byte below, the exact limit or one byte above. Each choice uses the same base: 3,145,728 B. Generate and download each file to test your endpoint.
Where a 3 MB JPG comes up
- Checking the error message a WordPress, Laravel or forum site shows for an image just over the default 2M limit.
- Testing the Django code path that receives an image as a TemporaryUploadedFile.
- Simulating an ordinary compressed phone photo in profile, listing and support-ticket forms.
Limits it lands on
- PHP's default upload_max_filesize is 2M, so this image is rejected with UPLOAD_ERR_INI_SIZE unless the host changed the value.
- Django keeps uploads under 2.5 MB in memory; at 3 MiB this one is streamed to a temporary file.
- Base64-encoded it is about 4.19 million bytes — still within a 6 MB Lambda request and under Vercel's 4.5 MB body limit.
What is inside the file
The browser draws an 800 × 600 test picture, encodes it as a baseline JPEG and inserts about 48 COM (comment) segments directly after the SOI marker to reach the exact length.
The picture data is untouched, so the image looks the same as the 1 MB and 10 MB versions; only the metadata area grows.
Questions
Why use 3 MB rather than 2 MB for PHP tests?
A 2 MB file sits exactly on the default limit, while a 3 MB file is clearly over it. Use both to test the boundary and the error.
Will an image optimiser change the file size?
Yes. Most optimisers remove comment segments, so the saved image drops to well below 100 KB.
Reference and checks
Format reference: ITU-T T.81 (JPEG).
Preset target: 3 MiB (3,145,728 bytes). Verify the downloaded file's byte count.
Generate another size in this format · Technical notes for every format · Guide to testing file upload limits · Data processing and privacy
Related tools: Image Convert · Resize Image · Compress Image.
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