Is upload speed generally faster through a FTP then uploading through the website?
It could very well be, but not necessarily. It all depends on how your network is configured, and how their site is configured. I doubt it will make a huge difference in upload speeds, to be honest.
Another thought I had, is it possible to set up something like what an action in Photoshop does? Something that records all the clicks that I do to upload to the sites only each time changing what pictures I choose?
I think you’re looking for a “macro”. Not sure which would be faster though… From the video tutorial I saw about Shutterstock, it looks like you still have to login after uploading your pics via FTP and submit them for review. So I’m not sure how much FTP would help in that situation.
It looks like WinSCP has a scripting feature that could upload a particular folder of files to multiple locations automatically. It would take some work to get the script setup, but then you could just run it, and it would upload the files to their respective FTP locations. That would definitely save some time! Do you always upload the same photos to all these different sites?