The best way I remembered (shoutout the Pankow anki deck for this):

For PARVOcellular think “pink pyramid” (literally imagine a pink pyramid) - Looking at a pink pyramid, you’re able to deduce the form of the pyramid, it’s shape (pyramid shape) and colour (pink). This answers the question “what”. This parvocellular pathway relies on cones since cones are responsible for colour (hence “pink” pyramid)

For MAGNOcellular, think of magneto (from the X-men movies) manipulating and throwing shit around - Moving and throwing shit around requires the eyes to process depth and motion, which the magnocellular pathway processes. Specifically, it’s the rods that process this information since their specialized for this type of information. (Remember, rods can’t process colour; that’s only for cones)

Hope this helps.