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When making prints it is usually better to have more pixels than you need rather than not enough, and generally when shooting it is a good idea to use the maximum resolution setting of the camera as quite-by-chance masterpieces can then be enlarged to respectable sizes.

The problem with shooting at the camera’s maximum resolution is that big pictures take up more room on the memory card, which means you won’t be able to fit so many on. The only proper answer is to get a bigger card, although there are tricks that can squeeze more images into the same space.

In digital photography compression is a method of condensing the information contained in your images so they take up less space. Little bits of data that the camera thinks it doesn’t need can be thrown away to make storage more efficient. For example, rather than the camera remembering pixel 1 is blue, pixel 2 is blue, pixel 3 is blue, and pixel 4 is blue, which requires eight bits of data to be stored it might just record that pixels 1-4 are blue – which could be stored as two bits of data; the range of pixels and their common colour.

Compression does not alter the physical size of the image – a 1.4 million pixel image will still be 1000x1400 pixels - but it does reduce the amount of data that has to be stored about that picture. With heavy compression an image can be reduced from 1000KB to just 88KB, which makes it easier to store as well as to transmit via email.

At maximum compression, some image detail has been lost in the second image.

Compression can create problems if too much data is thrown away. Image quality can suffer so we have to strike a balance. Your camera certainly won’t allow so much compression the image will be destroyed, but you should be aware that making large files small does come at the cost of quality. However for many images the effects of high compression will not be seen. If your images are to be shown small on a web site or only viewed on a computer monitor there is little point maintaining large file sizes as uses such as these do not need high quality pictures.

Creating small images in-camera can save you time as well as space on the memory card, but generally it is best to shoot images of the highest technical quality possible. Big pictures can be reduced in size and compressed on the computer if you want to transmit copies, and you can keep the bigger versions for printing. Images that have been shot small cannot be made big later and will never make high quality prints.