Is it possible to load an image into S3 via an URL? I'm going through some steps documented in How Do I Upload Files and Folders to an S3 Bucket? to get my ova into S3. Seems like a waste of time for me to download it and then upload it, is there a mechanism to import an S3 object from a web resource? 

I have a UCS Director job that builds OVAs for me, uploads them to a Cassandra big data cluster and serves out obfuscated links for me and customers to download them - I'd like to provide said obfuscated link to AWS instead of downloading it on my computer and uploading it to S3.  In the end, I think I could just make my images go straight from UCS Director to AWS, but for the time being, I'd like to save a step.
Nope, credit goes to this SO answer, still valid today: How to upload files directly to Amazon S3 from a remote server?.

But if you have a server in the cloud, ideally in AWS, it'll probably go faster to execute the copy operations on that server - higher bandwidth and lower latency to/from such server when compared to your computer.