A 25 MB JPG test file

About this file

A 25 MB test file in JPG format, sized to exactly 26,214,400 bytes. Free to download with no signup, for verifying upload limits and file-handling behaviour.

The MD5, SHA-1 and SHA-256 values listed above are the real digests of this file. Recomputing them after download confirms the transfer was not corrupted, and they double as known-good expected values when testing a hashing library.

What this size means in practice

25 MB is widely known as the Gmail attachment limit. In practice, though, mail attachments are Base64-encoded and grow about 33%, so a 25 MB file becomes roughly 33 MB on the wire and usually will not send as-is.

That gap between the advertised limit and the post-encoding size is a pitfall every mail-sending feature eventually hits. Use this file to check whether your size validation runs before or after encoding.

Getting a feel for this size

On a 10 Mbps link the transfer takes roughly 21 seconds, and about 2.1 seconds at 100 Mbps. Base64-encoded it grows to roughly 34,133 KB.

Estimating a photographic JPG at roughly 0.2 bytes per pixel, this size works out to around 131,072,000 pixels — about 13,220 × 9,915 px at a 4:3 aspect ratio. Compression varies enormously with image content, so treat this purely as an order-of-magnitude figure.

What to check for this format

JPEG is lossy and has no transparency. Its signature begins with FF D8 FF. The single most common defect in real implementations is ignoring the EXIF Orientation tag, which makes rotated photos appear sideways in the browser.

• Whether you read EXIF Orientation and auto-rotate, or deliberately strip it
• Whether privacy-sensitive data such as GPS coordinates remains — stripping is mandatory for user-submitted images
• Whether both progressive and baseline JPEG decode correctly — older decoders sometimes fail on progressive