I register my own QDeclarativeImageProvider and in the QML code, I do...

Image { source: "image://notes/f#" }

...but the id that is passed to my QDeclarativeImageProvider::requestPixmap() is just a f, not an f#. Quite a difference when rendering a musical note

Apparently, everything in the source URL after a '#' (inclusive the '#', itself) gets truncated. I assume, the reason is that the URL goes through a QUrl, and there a '#' marks the beginning of a fragment. The same happens also for ?, and that is a query delimiter.