This post features various images and image sizes including a gallery to test the download size of different setups. The post was created using the latest build of the Gutenberg plugin (as of Tuesday August 7 at 4:58pm PST) which includes the Responsive Images in galleries PR.
Note: All images are originally 1600px wide.Only default sizing and positioning is used to change appearance.
Full size image:
Large size image:
Medium size image:
Thumbnail:
Albany wind-farm against the sunset, Western Australia 
Antique farm machinery, Mount Barker Museum, Western Australia 
Orange Iris 
Rusty rails with fishplate, Kojonup 
Sea and rocks, Plimmerton, New Zealand 
Beach at Big Sur, CA