Some meta-commentary about some of the replies ... so far, there are 4+ replies suggesting the obvious step of storing in the images on the same web server host. But I notice the submitter is software engineer ex-Stripe, ex-Yelp, ex-Adobe... so I'm guessing he already knows that simple setup but doesn't locally host gifs & vids for technical reasons (bandwidth?, latency?).

Maybe recalibrate the suggestions based on the above. (Or the submitter can further clarify why hosting local image assets instead of using a CDN is not feasible in his particular case so the crowdsourced answers can be more productive to his goals.)

EDIT add: Sure, obvious technical answer may be applicable but some replies have a bit of condescension that doesn't seem appropriate and respectful of this person's tech background.