This is a very neat trick to unset max-height when an HTML element with resize='vertical' set in CSS is resized. So you can have elements initially displayed with a max-height but then resized beyond it:
@burritojustice The delay value associated with a GIF frame is after the frame, but that's not how MPEG timing works. So when converting from GIF to video you have to duplicate frame 0 as frame N with delay 0.
It also doesn't help that GIF measures that delay in 1/100th sec, which cannot represent normal frame rates of 1/30th or 1/60th sec as an integer.