Hey all, let me provide a little bit of how I discovered the "latest.jpg" concept. It may help in finding the right size picture and other things.
If you remove the latest.jpg from the url.... you'll see a directory of images.... I don't know how long they stay there, however you'll see there are a number of dated images... but there is also the "latest.jpg" image. and in the case of this URL
https://cdn.star.nesdis.noaa.gov/GOES17/ABI/SECTOR/wus/13/there are different size ones as well..
So if you find the image you're looking for, via some URL, remove the image name, and look at the directory. then choose the version (size etc) you want.
I’m pretty sure this is how NOAA is always displaying the "latest version". When a new file comes in, it creates the timestamped version and all the related sizes as the latest.
Remember too, that if you're capturing an image every 30 minutes, it takes a few hours to have enough different images to actually see it as a movie.
Hope this helps.
Ken