A 1 MB GIF test file

About this file

A 1 MB test file in GIF format, sized to exactly 1,048,576 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

1 MB is exactly the nginx client_max_body_size default (1m). Behind a reverse proxy where nobody set that directive, anything larger never reaches your application — nginx answers 413 Request Entity Too Large itself.

That makes it the ideal size for reproducing the classic incident where the app limit was raised to 10 MB yet uploads still fail at 1 MB. If the 413 never appears in your application log, the cause is almost always the proxy layer in front of it.

Getting a feel for this size

On a 10 Mbps link the transfer takes roughly 839 ms, and about 84 ms at 100 Mbps. Base64-encoded it grows to roughly 1,365 KB.

Estimating a photographic GIF at roughly 0.5 bytes per pixel, this size works out to around 2,097,152 pixels — about 1,672 × 1,254 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

GIF begins with the ASCII signature GIF87a or GIF89a and uses a palette of up to 256 colours. Because it can hold multiple animation frames, code written for single-frame images either grabs only the first frame or, worse, expands every frame and consumes far more memory than expected.

• Whether resizing an animated GIF preserves the animation or flattens it to a still
• Whether thumbnail generation correctly extracts the first frame
• Whether you cap memory when expanding all frames — usage grows with frame count multiplied by resolution