Animated Gif becomes 10 times bigger when published

Hi, Are animated gifs converted when published to Flash and HTML5. I have a page containing an animated Gif. I have been very careful in creating and optimising it (currently 1.7 mb). 

However when I publish the course (Flash and HTML5) the total SCORM package jumps from 3mb without the animated Gif to 33mb with the GIF. Looking in the published folders this single page is accounting for 15mb for both, flash and mobile i.e. 30mb total. 

I could go down a video mp4 route but I really need the auto start and looping of the animated gif.   

I'm using Storyline 2 currently.