The JPEG image format has been the staple diet of digital cameras for years. Its efficient compression levels make it the ideal space saver for those with less-than-generous memory cards.
But it's not just digital cameras which have reaped the benefits of JPEG compression. From mobile phones to the Internet, JPEGs are everywhere. But now there's a format on the horizon which threatens to dethrone JPEG; Microsoft's new WMP (Windows Media Photo) format.
Microsoft is going all-out to give its infant photo format the best start in life, including it in Windows Vista when it launches next year and releasing a Windows XP version around the same time.
Even so, making the humble JPEG obsolete will be no easy task. There is history: a couple of years ago JPEG 2000 was launched and, despite sounding like a bad millennium village disco, was lauded as the spiritual successor to JPEG, offering superior image quality and greater levels of compression.
What's more, it offered both lossy and lossless compression, whereas standard JPEG is always lossy.
JPEG 2000 seemed like the answer to photographers' prayers. As with other, less widely supported image formats, its "lossless" compression method shrunk images without sacrificing quality. Even so, far from seeing off the JPEG format, JPEG 2000 faded into obscurity without many of us being aware it existed.
Meanwhile, other formats have stepped up to the mark. JPEG may still be the most camera-friendly format but some cameras let you save shots as TIFF or as RAW files.
Normally found on pricier compacts or D-SLR (digital single lens reflex) cameras, TIFF and RAW files produce better quality results than JPEGs. But files are larger, so you can save fewer to a memory card. For this reason we don't recommend shooting TIFF unless you have a glut of large memory cards.
RAW files are worth experiment-ing with and have some genuinely unique features. You no longer need an expensive photo editor to make use of them either - pretty much every photo editor currently on the market has some degree of support for RAW.
RAW isn't actually a format, it's the original unprocessed (ie raw) data taken from the camera's sensor at the time of capture. The data becomes an image only once it's opened on a PC. It allows an unprecedented amount of post-shot fine tuning, including white balance, sharpness and exposure adjustments. It has become the professional-photographer's file format of choice.
RAW files are big, though. An image taken with an 8Mp (megapixel) camera will be 7-8MB. A 256MB card will be stuffed to bursting in a little over 35 shots.
The other downside is that nothing happens particularly quickly. Shots take longer to be cleared from a camera's buffer, affecting the burst speed and how many snaps you can take in continuous mode. Browsing them on a PC can be pretty painful, even in a powerful program such as Photoshop.
All of which means RAW isn't exactly mainstream. This brings us back to the humble JPEG and, more to the point, its replacement. Microsoft's WMP tries to bridge the gap, offering quality and definition close to that of JPEG 2000 at file sizes similar to that of ordinary JPEG.
WMP is geared to retain more photographic information, including a greater dynamic range than JPEG, and offers the choice of lossless or high-quality lossy compression using the same algorithm. Compression is the real talking point here. Microsoft says WMP will deliver a better perceived image quality at more than twice the compression of JPEG, meaning file sizes should be much smaller.
WMP has other tricks up its sleeve, too. It will support transparencies (aka alpha channels) and more colour spaces than the usual RGB, CMYK and monochrome. One of its neatest features is likely to be its ability (with supported hardware) to process a region of a larger image file without draining processing power from the entire PC. So when working with large files, you should spend less time waiting for the computer.
Upgrade or buy?
Overall Microsoft's format sounds dandy, but what this means to existing cameras and other hardware is unknown. We guess using the format would mean buying a camera rather than performing a firmware upgrade. What this means for JPEG - both existing files and the format itself - is another unknown, but we're sure Microsoft has a game plan for that too.
As with any format, becoming the new standard won't happen overnight, if at all. But with a launch scheduled to coincide with the release of Windows Vista, it'll be 2007 before we really get to see what WMP has to offer. Meantime, don't be surprised if one or two cameras start gearing up for it with promises of "WMP-ready".
Lossy compression means that non-essential information such as finer detail and some colour data is discarded to keep files sizes minimal. If you like to tinker with JPEGs on a PC, you'll find the image gradually degrades with each successive save as compression is applied. Eventually, the constant editing and resaving will reduce the picture quality to the point where it starts to resemble Russian television.
Some experts suggest that you may notice a difference after only six saves or so.