Many things have changed about the iPhone since the first one launched back in 2007. One thing that has remained constant, however, is the phone’s screen size. Retina display notwithstanding, Apple’s fifth iPhone – the iPhone 4S – sports the same 3.5-inch screen as their first iPhone.

The fact that Apple has kept the iPhone’s screen size consistent through five generations of phones has not stopped repeated speculation that the next iPhone would have a bigger screen. Now Chris Caso, analyst for Susquehanna, is predicting that Apple’s sixth iPhone will finally be getting a larger screen. In a note sent to clients this morning, Caso predicted that Apple would begin production of their sixth-generation iPhone – which most analysts are calling the iPhone 5 – in June of 2012, and that it would sport a 4-inch screen.

This is going to have to go in the “believe it when I see it” file. As already noted, Apple has consistently – almost stubbornly – kept the iPhone’s screen size the same. As Android phones of all sizes have come into the market, Apple has held to the 3.5-inch screen. While anything is certainly possible, Apple tends to be a creature of habit when it comes to things that work, and the iPhone’s 3.5-inch screen has worked well through five generations of iPhones. It doesn’t seem likely that they’ll change it now.

[Images Source: ADR Studio]