Twitter has increased its GIF size limit from 5MB to 15MB. But you won’t be able to enjoy this increase if you’re tweeting on mobile. Only when you tweet via Twitter.com on the web will you be able to post GIFs larger than 5MB.
I know right? Not nice, since we mostly access twitter with our phones.
Twitter seems not to have made a big fuss about this change as the news broke not through a formal announcement by Twitter but rather from avid GIF users and Twitter Support watchers.