Wow! I thought I was the only person who encountered this limitation with Penultimate. Instead of using paper to take handwritten notes for my financial services business, I have started using my iPad Pro and Penultimate. My office had created some forms to fill in with basic information when meeting with someone for the first time AND due to more and more regulatory expectations, we also have been wanting to use forms for meetings that are organized in the way our regulators like. Yes, you can insert an image file as a background to annotate, but whenever I have tried this they show up as all fuzzy. Also, it is difficult to insert a different form/background when adding a new page.
Penultimate gives the best user experience out of any note-taking app I have experienced, however, I have started looking at other apps, which stinks because it means buying each app to try it out. Please improve the functionality of creating custom backgrounds for notes and being able to easily choose different backgrounds for different pages of your notes.