Create a new forum, add a new discussion with some posts including inline videos or images (not attachments, I'm talking about images and videos embedded in the rich text editor). Already done on prototype 3.4 > Moodle Mobile Dev testing > Forum > Standard forum... A a teacher, in a quiz: grade an student and add a file/image in the rich text editor on feedback. Recomended doing it on prototype 3.4 > Moodle Mobile Dev testing > Quiz > Offline quiz with password... In a glossary: add some image to the definition in the rich text editor.. Already done on prototype 3.4 > Moodle Mobile Dev testing > Glossary > Main glossary... Now, from the app, try to prefetch this activities and then go offline. Reach the point you see the image and check you can view them.