'Lazy load' jquery plugin doesn't work with gif2video enabled

[Ackar]

The Lazy load plug-in relies on an additional data-original attribute in img to load images asynchronously. Changing the img tag to video breaks that (even when preserving the data-original attribute).

Step to reproduce

• Enable gif2video
• Go to a website using the Lazy load plugin

[eamsen]

The test link is dead, but it's clear why gif2video breaks it. Modifying the DOM will always bring risks like this, so we should look for standard-conformant alternatives to make GIFs more efficient.

[eamsen]

Actually, we shouldn't replace <img> if no src is given and may filter any tags with class attributes to be on the safe side.