Hi Zotero Team,

I heavily rely on Zotero's built-in PDF reader for my academic research. However, I constantly run into a frustrating limitation regarding the PDF annotations.

The Use Case:
When reading papers with complex equations, I often don't understand the formula right away. I usually find the step-by-step derivation from other sources (like a textbook or a website), take a screenshot of that derivation, and want to attach it directly to the formula in the PDF.

The Problem:
Currently, the annotation popup (when clicking on a highlighted text or an area) only supports plain text. I cannot paste an external image (like my screenshot) into the annotation popup, nor can I paste an image directly onto the PDF margin as a standalone object.

Creating a separate "Item Note" for every single formula derivation breaks the reading flow and makes it hard to see the context at a glance.

Feature Request:
Could you please consider adding rich-text/image support to the PDF annotation popups? Or, alternatively, allow users to paste clipboard images directly onto the PDF page as an "Image Annotation" object? This would be an absolute game-changer for anyone in STEM fields.

Thank you for your amazing work!