Why Does This Site Cap GIFs at 900px Wide?

Every so often someone asks me, “Why can’t the output width go past 900px?” I didn’t block it for no reason, so here’s my thinking.

For reference, the longer side is now set automatically by the quality level, from 320px (Low-spec) to 900px (High-spec), and nothing is upscaled past the original. 900px is the limit of the highest level.

1. Big GIFs get way too heavy

GIF is an old format that only uses 256 colors per frame. It’s weak at the kind of compression modern video formats rely on, where only the parts that changed from one frame to the next get stored. So the bigger the frames and the more of them you have, the more the file size just keeps piling up.

On top of that, when you make it wider, the height grows along with it to keep the aspect ratio, so the pixel count goes up with the square. Double the width and you get four times the pixels.

In the settings guide, a 4.5-second video at 900px with a 0.1-second interval came out to 14MB. Under the same conditions, bumping only the width to 1800px means four times the pixels, so by simple math you’re well past 50MB. That’s an awkward size to put on a blog or send through a messaging app.

2. The conversion runs on your browser’s memory

This site doesn’t convert on a server. It does the work inside the browser you’re looking at right now. When it encodes the GIF, it lays the frames out as uncompressed pixels, and the sizes work out like this:

One frame = width × height × 4 bytes (red, green, blue, alpha)

900 × 506   → about 1.8MB
1920 × 1080 → about 8.3MB

If you take a 10-second video at full 1080p with a 0.1-second interval, that’s 100 frames, or 830MB. That’s exactly the kind of number that freezes a tab on a phone or a laptop without much memory. At 900px, the same conditions come out to around 180MB, which most devices can handle. Conversion time also goes up with the pixel count, so a smaller size means faster conversion too.

3. Nobody sees them that big anyway

In blog posts, messaging apps, and social media feeds, GIFs are almost always shrunk to fit the screen width. On a phone, the screen is around 400px wide in web terms. Making a GIF bigger than 900px makes almost no difference to the person looking at it. It just loads slower.

So, 900px

900px is the line I drew between image quality, conversion speed, and the load on your device. It isn’t necessarily the one right answer. It’s the cutoff I picked to stick to this site’s basic rule: anyone should be able to use it in their browser without it being a strain.

If a lot of people really need bigger GIFs, I’ll think about lifting the limit on desktop only. If that’s you, let me know through the contact page.

If this helped, sharing the link would mean a lot. I run this site on my own.