Marco Arment posted a follow-up article today in regards to his latest finding with his personal iPad mini. Over a year ago, image retention started popping up in multiple user experiences on the Retina MacBook Pros which led him to create a simple test image. This can "detect" whether or not you have a faulty LCD screen and once again it applies here to Apple's new iPad mini with Retina Display. It comes without mentioning that if you have a Retina MacBook Pro, you can look up your model ((The manufacturer that had the most hits for positive image retention came from LG while the Samsung variant produced far less instances.)) by running this simple command in the terminal window:
ioreg -lw0 | grep "EDID" | sed "/[^<]*</s///" | xxd -p -r | strings -6
credit: MacRumors user: kpdillon
With the new iPad minis selling out this week and other LTE versions shipping out next, you should give this test a shot immediately when taking delivery. And if you're able, exchange the product if you demonstrate image retention. As Marco also mentions, because of the short supply, the chances of an exchange can be hindered but if you plan on keeping your iPad mini for years to come, I'd highly recommend trying as best to squash the problem before it's too late.
On a good note, not all screens are presenting this issue as he also goes on the mention that the new iPhone 5s and iPad Air do NOT exhibit this symptom.
Here's his direct link to the screen test.