TL;DR: This UPDATED workflow works with current versions of IPAdapter, and is significantly simpler and faster than v1.0, thanks to IPAdapter's new layer filtering feature that allows you to ignore the IPAdapter's content layers and focus on style alone. It can be used both for generating new images and restyling existing ones.
YOU NEED CONTROLNET++ PROMAX FOR IMAGE STYLE TRANSFER.
I'm retaining v1.0 here mostly as a curiosity, in case you're running an old version of IPAdapter and ComfyUI for whatever reason. v1.0 will not work on current ComfyUI IPAdapter versions.