Ask students to explain in their own words what they want from the image, audio and video files they use. Are they worried about the size of the files or the quality of the image or sound? Does size ever cause problems because they run out of space on their phones or if they want to share them with friends? Could they imagine a situation where that might happen?
Check what formats are used for the image, audio and video files they have on their phones. Do they notice any difference in quality between the images?
Encourage the students to provide examples, drawing on their own experience if possible.
Tell students that they will need their lecture notes from this lesson in the next lesson.