Loading slider images async

Hi Guys, I′m using the flickity slider and I have some pretty large images in there. Now to avoid having all these images in the html source which would increase the initial loading time tremendously, I only want to place the first slider item into the html and load the other slider content and images later via AJAX.

Is that a good idea or is there a simpler solution?
And IF this is is a good idea I′d have to use the REST API, but I′m not sure if it is ready to use yet?
Thanks!