We've talked previously about megapixels as they relate to image size. Most cameras allow you to make photographs at various megapixel settings. If you're serious about your photography, you should always shoot at the highest setting. For example, if you have an 8 megapixel camera, make sure you're shooting at 8 megapixels. Don't settle for anything less than the maximum.

Keep Your Original Safe

A good practice is to always keep your original files untouched, just as they came out of the camera. If you need one of your photos in a different size, make a copy to tinker with and keep the original just as it was. There are many reasons for not messing around with your original files:

1. JPEG compression. If your original is a JPEG, every time you re-save the image as a JPEG it is being re-compressed, crunching away at the quality of your photograph. Leaving an original untouched allows you to go back anytime to mint condition.

2. Pixel data. As I've mentioned, changing the color and tonality of your image in a program like PhotoShop causes you to lose pixel information. Having that original to go back to, with the complete image data, can be a lifesaver if you screw up the copy.

3. Future considerations. No matter how good you think you've made your photo look today, I guarantee you will find another approach in a year or so. Having that original around lets you start from scratch with the original recipe.

Re-Sizing Photographs

There's a basic rule in the digital world. You can always make a photo smaller without any loss in quality. You cannot, however, make a photo larger. The pixel data you have when you made the exposure is all you've got.

There are various software packages that will upsize your photograph through interpolation and some of them work quite well. But the type of image enhancement that you see in the movies and television, where a pixelated license plate comes miraculously into crystal clear focus, simply does not exist.

If you need to enlarge the pixel size of your image the best results come from doing so in small jumps rather than one giant leap. So increasing the size of your photo by 10% several times in a row will give you a higher quality upsample than one large increase.

Emergency Considerations

Of course, shooting at the highest image size on your camera means your photographs will be larger files, filling your memory card quicker. If you find yourself running out of memory but need to keep shooting, you may have to lower the quality of your photographs. To keep your quality high in a case like this, follow these steps as needed:

1. If you're shooting RAW, switch to the highest quality, largest size JPEG. If just doing that gives you the space you need, stop here. If you still need space, continue to step 2.

2. If you're shooting JPEG, lower the quality of your JPEG file. Start in the smallest increments, checking your camera's readout to see how many images the change frees up.

3. As a last resort, lower the size of image you are capturing. That is, shoot at a lower megapixel setting. I consider this a last resort, as I'd always rather have more pixels.