Framebench can do that.
Hit the link below to learn more, or to give it a whirl.
Annotate Attachments in Gmail - Framebench(Free) | Chrome Web Store viaFramebench - Mail Markup in Gmail
FrameBench Annotates Attachments Inside Gmail, No Downloading Required
Chrome: It's not terribly difficult to download email attachments and add your notes to them if you need to, but wouldn't it be nice to review the att
