If you're building this HTML dynamically, just append ?t=<current unix timestamp> to the URL of every image. That way, the browser will have to load them from the server every time because the URL will always be different.

Alternatively, you could configure your web server to send "don't cache" headers when it sends those images (but this is probably more difficult and overly complicated).

If you're building this HTML dynamically, just append ?t=<current unix timestamp> to the URL of every image. That way, the browser will have to load them from the server every time because the URL will always be different.

Alternatively, you could configure your web server to send "don't cache" headers when it sends those images (but this is probably more difficult and overly complicated).

I do question the use of srcsets for this purpose. It might work, but I'm not sure srcset is the best tool for the job, or that srcsets are intended to be used in this way. If you're switching the actual image, it seems like that ought to be done by two different image tags, each with its own srcset (which you can show/hide at different resolutions), or with some JS solution of some kind.