The retouching plug-ins can intelligently change the contrast, color, sharpness, and many other common filters to make a picture look as crisp as possible. The special effects plug-ins are my favorite, because they can make a rather plain image into something fantastic. If you use Photoshop on a regular basis, then you need to look at some of the plug-ins that are available, because they can make your life much easier, and your graphics look much better.
There are a few formats for digital photography, different formats have their own advantages. For instance the jpeg format is the default format used by almost every digital camera ever made. Named after its developer, the Joint Photographic Experts Group (and pronounced "jay-peg") this format often lets you specify both image size and compression. At the moment you capture an image in this format a processing chip in your camera manipulates it based on the camera settings you used, and then compresses it to reduce its size. The changes made to the image cannot be undone later because it's the final, altered image that is saved in the image file. Some of the original image data is lost for good. This is a handy format because it is the most basic and commonly used.
Image files are huge compared to many other types of computer files. For example, files captured by a 12 Megapixel camera can range up to 18 Megabytes. As resolutions continue to increase, so will file sizes. To make image files smaller and more manageable, digital cameras use a process called compression. During compression, data that is duplicated or that has little value is eliminated or saved in a shorter form, to reduce a file's size. For example, if large areas of the sky are the same shade of blue, only the value for one pixel needs to be saved along with the locations of the other pixels with the same color.
When choosing between JPEG and RAW formats, here are some things to consider about each format. Because you can't easily add pixels and retain image quality, or remove the effects of compression after the fact, it's usually best to use the largest available JPEG size and the least compression available. If you have to reduce either, you can do so later using a photo-editing program. If you shoot the image at a lower quality setting, you can never really improve it much or get a large, sharp print if you want one. The only problem with this approach is that higher quality images have larger file sizes. RAW images are always captured at the largest file size, and any compression used is lossless. Images in this format used to require an extra processing step but since the latest programs such as Aperture and Lightroom were designed from the ground up after RAW formats were introduced they handle them as easily as they handle JPEGs.
If you use operating system tools or applications to look at a storage device in the camera or card reader, you will find it is listed like the other drives on your system. If it contains more than one folder, the one photographers care about is named DCIM (for Digital Camera IMages). If you delete this folder, the camera will recreate it (but not any images it contained). The purpose of this folder, called the image root directory, is to keep together all of the images you capture with the camera. If you use the same card with other devices, there may also be other folders on the same card holding MP3 music or other files.
When an image is saved, the camera assigns it a filename and stores it in the current folder. Filenames have two parts, an 8-character filename and a 3-character extension. Think of them as first and last names. The name is unique to each file, and the extension, separated from the name by a period, identifies the file's format. For example, a JPG extension means it's a JPEG image file, TIF means it's a TIFF image file.
IPTC: Using an image management application, you can add information to an image such as keywords, a copyright notice, or a caption. The problem is that when you send the image to someone else, that information is usually not sent along because it's stored on your computer in the database and is not part of the image file as Exif information is. (As you will see shortly, one solution to this problem is the xmp file.) To solve this problem, the International Press Telecommunications Council (IPTC) defines a format for exchanging such information. Programs that support this standard let you add, edit, and view this information that's embedded in a file just as Exif information is.