Image audit: check for animated GIFs that could be videos

[samdutton]

Video with muted autoplay can often be used instead of an animated GIF.

If an image element is found with GIF src (over, say, 20KB in file size) give a warning, something like: 'It appears that you might be using an animated GIFs. Consider using a video (with autoplay muted) instead.' If possible, link to video version of animated GIF and advice on transcoding.

[wardpeet]

It looks like we can do something like https://github.com/mailcharts/animated-gif-detector so we make sure it's an animated GIF.

I guess this audit should be placed under Do better web?

[paulirish]

I guess this audit should be placed under Do better web?

eh. ideally our /audits/ folder is grouped by category a bit more... kind of like https://github.com/Modernizr/Modernizr/tree/master/feature-detects

[paulirish]

animated-gif-detector looks great. yeah i think that'd work out nicely.

[brendankenny]

was fixed in #4885!