With the iPad3 launch, existing applications would not use retina graphics even if they included them. They had to be re-linked with the latest SDK.
Apple has a long history of doing `linked-on-or-after` checks for compatibility with various older paradigms or iOS versions. As such, I don't think throwing a screenshot into a directory will make the app actually run at full size. It might mollify iTunes Connect, but mollifying iTunes Connect is just one facet of shipping an app: the runtime is a completely different animal.
This is even a difficult condition to test, as installing an app in the 6.0 simulator without rebuilding it for the 6.0 simulator and thus passing the linked-on-or-after checks (and as such, with Xcode 4.5) is nigh-unto impossible, as the 6.0 simulator does not quite predate Xcode 4.5 as the beta versions could very well fall under the "or after" part of the link condition.
Apple has a long history of doing `linked-on-or-after` checks for compatibility with various older paradigms or iOS versions. As such, I don't think throwing a screenshot into a directory will make the app actually run at full size. It might mollify iTunes Connect, but mollifying iTunes Connect is just one facet of shipping an app: the runtime is a completely different animal.
This is even a difficult condition to test, as installing an app in the 6.0 simulator without rebuilding it for the 6.0 simulator and thus passing the linked-on-or-after checks (and as such, with Xcode 4.5) is nigh-unto impossible, as the 6.0 simulator does not quite predate Xcode 4.5 as the beta versions could very well fall under the "or after" part of the link condition.