Keep output resolution in mind. 300x300 onscreen needs to be 900x900 for a 3x "retina" display.

This also falls into the "premature" optimization camp. Make sure you have a problem before coding for a solution, as image scaling isn't free, and a badly implemented caching scheme can cause you to end up in the same hot water in regard to memory management.

Finally, resizing such as this is pretty simple to accomplish using the tools we already have in UIKit, without the need for an external library as suggested by the article.