The launch of the white iPhone 4 could be being held up by camera issues with the device, Apple co-founder Steve Wozniak has said.

The white-painted glass meant that photos taken with the flash on looked as though they were taken through cellophane, Wozniak said, adding that he had managed to replicate the problem by buying parts for the original white iPhone 4 that were never shipped.

The problem could lie with the amount of light that the white iPhone 4 lets in or leaks when the flash is used to take a photograph.

Speaking on the Engadget Show, Wozniak said that he planned to buy two Verizon iPhones - one in black and one in white - when they launch.

The launch of the white iPhone 4 was supposed to happen when the black iPhone 4 launched in July 2010. However, Apple admitted a week before launch that it would be delayed until the end of the year.

Apple recently confirmed that the launch of the white iPhone 4 would, in fact, happen in the spring of 2011. One or two network operators - Orange and Three in the UK - jumped the gun slightly by adding the white iPhone 4 option to their websites last week, though no official announcement had been made.

Orange and Three both told Macworld that the white iPhone 4 option had always been on their websites, in preparation for the official launch of the device, though neither could shed any further light on when that might be.

During Wozniak's appearance on the Engadget Show, he also found time to praise the Android OS, singling out Voice Actions as one area where Google's open source mobile OS had the edge over iOS.

Only today, analyst firm Canalys released figures suggesting that Android had become the best-selling mobile OS.