srcset attribute in Gutenberg gallery blocks

[aitormendez]

Gallery block are very useful to layout thumbnails. However, when I choose a columns layout (for example, four columns layout), the srcset for this thumbnail remains the same as a large image.

In other words, with a four columns layout, the thumbnails srcset come with:

sizes="(max-width: 768px) 100vw, 768px"

So, all thumbnails are built with the large images. For example, in this page: https://stage.margenesdelarte.org/productions/relato-de-salida-al-albergue-2018/

Is it possible to get something like this?:

sizes="(max-width: 768px) 100vw, 200px"

Further more, is it possible to set srcset up regarding the number of columns in the gallery block layout?

[swissspidy]

Related and possible duplicates: #6177, #5674

[youknowriad]

Duplicate of #9620