Sancha,
Here at SHU the graphic design team has been using the use iPhone audio feedback approach this year, which could be interpreted as interesting concept when the subject medium is visual.
There are screencasting type apps; Notability or Explain Everything apps (links to my blog entries reviewing these apps for learning) on the iPad may lend themselves or maybe more appropiate for a visual subject as can import or take a photo image in the app, the user can add write/type comments, arrows, image overlays etc on top of the imported image and audio record the users verbal feedback, [...]
This is an archive of the 2013 version of ocTEL.