Images · PNG
A 30 MB PNG file, on demand.
Exactly 31,457,280 bytes of a real truecolour PNG with a gradient, not a placeholder rectangle, built on your machine the moment you press the button.
31,457,280 bytes, exactly.
Every byte above the 288 bytes structural minimum goes into a tEXt metadata chunk with a valid CRC, which decoders skip, which is why this file still behaves like one a real user would send.
Unit convention
30 MB on this page means exactly 31,457,280 bytes, using the binary (MiB) convention some systems label "MB" for short. 1 MB in the strict decimal sense is 1,000,000 bytes; 1 MiB is 1,048,576 bytes — the readout above always shows the exact count either way.
Approximate size equivalents
Roughly 17,476 pages of typed text, 33 minutes of 128 kbps audio, 3 minutes of CD-quality audio, 13 photos from a 12 MP camera. These figures compare file size only — the generated file does not contain this text, audio or image content.
Accepted by
Cloudflare Free proxy body, GitHub repository file, Slack free workspace file — all publish a limit at or above this size, based on commonly cited figures that can vary by plan and change over time.
Rejected by
Gmail attachment, Outlook.com attachment, Discord free attachment — this exceeds their commonly cited limit, which makes it a useful negative test. Published limits can vary by plan and change over time.
Other PNG sizes
Files this large exercise multipart and chunked upload paths rather than a single request, which is usually where the bugs are.
Questions.
Is this 30 MB PNG file valid?
Yes. It is a real truecolour PNG with a gradient, not a placeholder rectangle. The extra bytes sit in a tEXt metadata chunk with a valid CRC, which decoders skip, so it opens in Preview, Photoshop, browsers and Pillow.
Does 30 MB mean 31,457,280 bytes?
On this page, yes — 30 MB uses the binary (MiB) convention, so the file is exactly 31,457,280 bytes. 1 MB in the strict decimal sense would be a different, smaller byte count. Upload validators may use either convention, so the exact byte count is always shown to remove any ambiguity.
What is a 30 MB file used for?
Files this large exercise multipart and chunked upload paths rather than a single request, which is usually where the bugs are. For PNG specifically, the usual job is checking image upload limits, CDN behaviour and thumbnail pipelines.
Where is the file downloaded from?
Nowhere. It is assembled in a Web Worker on your own device and handed to the browser as a Blob, so nothing is uploaded, fetched or stored.