A leaked image of an iPhone 5 engineering sample has shown the device with an enlarged screen compared to the current iPhone 4S. With the release date of the iPhone 5 expected in September or October, rumors of the new device are picking up pace as analysts attempt to identify specs for Apple's next generation smartphone.

Shots have been obtained by GottaBeMobile.com which has reported that the engineering samples were handed over from a reliable source in a China factory. If the source does in fact prove reliable then the iPhone 5 would have a larger screen similar to a widescreen 16:9 aspect ratio.

The news is exciting for Apple fans, as the change of foundational design indicates major upgrades for the iPhone. Many iPhone users were initially left disappointed last year when the iPhone 4S was released with exactly the same design as the iPhone 4. Although there were a number of upgrades released with the iPhone 4S, such as Siri, the changes were relatively minor, and the handset was not changed in any major way.

The new photos show the iPhone 5 with a camera in the same place as the iPhone 4S but features a microphone sandwiched between the lens and the flash. The back plate has previously been rumored to be made of metal, but this cannot be confirmed from the new photos.

The new photos come as other reports claim Chinese retailers are already offering pre-orders for the iPhone 5. According to Reuters a website called TaoBao is offering Apple fans the chance to reserve the iPhone 5 on a page that displays mock-up pictures and unconfirmed specifications for the new smartphone.

According to the Reuters report TaoBao is China's largest e-commerce platform, and its listing offers the new iPhone at the hugely inflated price of $8600.

Tags: iphone 5