How does Automator (Mac) compares to Photoshop based on reducing images to thumb size?

for a client website of mine I reduce each photo manually to 'thumb size' (height 200px). One of the other actions I have to execute is replace each space with a dash character. I automate this with a automator script.

However, Automator can do much more- and this includes reducing images. However, this is for a photography website and quality matters most. I do have to admit that I doubt 99% of all can distinguish the pixels from a automator action and a manual photoshop reduce action- but I still wonder how much in quality Automator differs from a manual reduction in Photoshop.

This to determine if I can automate the reduction of images too.

I am going to test this myself, but I wonder about your replies.