Images · PNG
A 1 GB PNG file, on demand.
Exactly 1,073,741,824 bytes of a real truecolour PNG with a gradient, not a placeholder rectangle, built on your machine the moment you press the button.
1,073,741,824 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
1 GB on this page means exactly 1,073,741,824 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 596,523 pages of typed text, 1118 minutes of 128 kbps audio, 101 minutes of CD-quality audio, 429 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
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
Cloudflare Free proxy body, GitHub repository file, Gmail 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
At this scale you are testing infrastructure rather than validation: timeouts, proxy buffers, disk headroom and progress reporting.
1 GB in other images formats
Questions.
Is this 1 GB 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 1 GB mean 1,073,741,824 bytes?
On this page, yes — 1 GB uses the binary (MiB) convention, so the file is exactly 1,073,741,824 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 1 GB file used for?
At this scale you are testing infrastructure rather than validation: timeouts, proxy buffers, disk headroom and progress reporting. 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.