It does use it. You need inline expansion or image hover enabled in settings though - 4chan has traditionally had minimal or no Javascript and this is an artifact of it.
Please don't. gifs are constrained by file size and usually 10-20 seconds or less. When you approach the minute range being able to navigate through rather than watching the whole thing again becomes valuable. Thankfully there's no sound, so at least there's no issue with volume levels.
and then, instead of using a browser, use a platform specific app. Persist user agent data so you can remove the captcha, and it will be just like the original 4chan.