This is nicely illustrated by Chambers and Reisberg’s (1985) finding that when individuals are shown a picture of an ambiguous image for 5 seconds, a period to short for them to discover the alternative interpretation, and then asked to find the alternative interpretation through recall, subjects fail to find the alternative image. However when asked to draw the ambiguous figure from memory they can discover a second image in what they’ve drawn. People find it impossible to find different interpretations in their mental imagery, a difficulty they don’t have when presented with a picture on a page. (Kiverstein & Farina, forthcoming, p. ???)This is just the kind of evidence that Pylyshyn, for example, uses to argue that mental imagery is not a matter of having little pictures in the head. It's just the kind of thing that makes A&A not really worry about Menary's appeal to mental imagery to challenge the non-derived content condition on the cognitive.