Image assets are PNGs regardless of content

[P33M]

For example - loading the Getting Started page results in an 11MB download, and the vast majority of this bandwidth is due to the inline images.

On slow connections/devices (such as earlier Raspberry Pi computers), there is very noticeable lag when rendering the page.
PNGs should not be used to serve content that's primarily photographic - they should be JPEG/WEBP.