Old Toad wrote:
I've used this app for a number of years. It's an excellent add on tool for my image editing apps. Many times 3rd party apps meet needs that Apple just doesn't address.
Automator doesn't have any such capability.
I ended up trying Resize and ran into a couple of issues. One it's not a signed developer so you have to "Open" it from the contextual menu. More importantly, I had a warning dialog that the program could slow my computer. when I tried selecting a folder of images to convert, it took a while for the Open dialog to appear, a while to select a folder, etc. Once set up it converted the images fairly quickly. High Sierra 10.13.3
I would also mention XnConvert. Also free and supports 500 image formats, has more features.