For example :
I have thumbnail of image in fixed size block 250x250px. And three images:
<img sizes = "250px"
src = "image-250w.jpg"
srcset = "image-250w.jpg 250w,
image-500w.jpg 500w,
image-750w.jpg 750w"
>
So browser pick candidate 250w for device with DPR: 1.0, 500w for device with DPR: 2.0 and 750w for device with DPR: 3.0.
So what the visual difference between these DPR 1,2,3 for human eyes?
I don't have devices(iPhone, etc.) with different DPR to see this. And device emulations can't show me this while I do it on same display.