I was recently reminded of an old article that I wrote back in 2013 demonstrating how to capture Virtual Machine screenshots using a couple of options that are available within vSphere. While the blog post is more than 10 years old, the guidance and options are still applicable for all recent vSphere releases.
I highly recommend folks give the original article a read, especially for the full background but I did want to provide some updated information for those interested in automating the capture of VM screenshots using both the vSphere API as well as the HTTP Handler methods.