I've encountered issues where Adobe ColdFusion wasn't able to read JPG photos from our clients that were created using an iPhone 4. As a result, we started using CFExecute with GraphicsMagick for all of our image transformations. (GM is also used by Etsy & Flickr.) I've tested ImageMagick it also works. (We also have IM installed so we can convert HEIF/HEIC images to JPG automatically upon upload.)
I used this WEBP image for testing:
https://www.gstatic.com/webp/gallery/1.webp
Original Filesize: 10,474
GraphicsMagick:
gm convert c:\test.webp c:\test.jpg
Resultant Filesize: 12,338
ImageMagic
magick c:\test.webp c:\test.jpg
Resultant Filesize: 25,132