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.
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.