I recently ran into this problem on my HTC One XL: I flashed a new ROM and realised my girlfriend had recently added notes that we needed. I found them on the sdcard partition under .data/HtcNotes. Given I'm running a non-standard ROM I could just mount my phone as a mass storage device and browse to the folder. If you want to look at them on your phone, then you can do that too using the ES File Explorer app (I have no affiliation with them, I just know that it works) after enabling hidden folders in the settings.
FYI, this directory seems to contain a hidden directory for each note, and each directory contains (possibly among other things) a content.html file that has the textual contents of your note saved as HTML. I'm guessing that other media types would be saved within these directories, but I don't have any to test with.