In 2016, Luke Lyons (FLIR) shared a sanitized version of their Authoring Style Guide because understanding and managing graphics in Windchill can be somewhat confusing. He nailed down the procedures for bulk upload and for updating graphics in XML content. He shared it with us with the understanding that we would share it with others.
This is their internal procedures document (minus the stuff they cannot share). Things they learned and documented for processes and best practices they didn't want to have to remember.
Bulk uploading of graphics to Windchill
Getting Landscape pages to work
Working with Baselines
Translation and XLIFF tips