I wish both srcset and elements wouldn't be so redundantly verbose by forcing you to specify the full (relative) URL for each image when they usually only differ by a small part specifying the resolution or format. Sure, transfer-encoding will mostly nullify the overhead but it's still annoying when editing the HTML manually.
Ah, don't edit the HTML manually. Name your images brain-dead predictably, and use a script with some regex.
My blog has some code that searches for tags just after markdown conversion, then uses the src to find similarly named images (image×1.jpg, image×2.jpg, etc.) to use in tags.
