A 100 MB GIF test file

About this file

A 100 MB test file in GIF format, sized to exactly 104,857,600 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

100 MB is GitHub's hard per-file push limit and also the upload cap through Cloudflare's free plan. It is likewise the point where AWS S3 recommends multipart upload instead of a single PUT.

It also exercises your timeout configuration. On a 10 Mbps link the transfer alone takes about 80 seconds, so leaving PHP's max_execution_time (default 30s) or nginx's fastcgi_read_timeout (default 60s) untouched makes the upload fail on a timeout rather than on a size check.

Getting a feel for this size

On a 10 Mbps link the transfer takes roughly 83.9 seconds, and about 8.4 seconds at 100 Mbps. Base64-encoded it grows to roughly 136,533 KB.

Estimating a photographic GIF at roughly 0.5 bytes per pixel, this size works out to around 209,715,200 pixels — about 16,722 × 12,542 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