Improving Responsive Images with the Picture Element

The topic of providing the right image (in terms of size and pixel density) to a given device has been discussed extensively over the years.
The browser is provided with a set of "suggestions" about the correct behavior with certain types of images, thus improving the loading time of a page.
This technique reduces the weight of a website for devices with small screens (that we tend to think of as devices with a slow connection), and so improves user experience.
A while ago the srcset attribute was a standalone proposal but has since been incorporated into a wider proposal, the picture element. ...