Understanding the pixel-resolution connection

Image resolution refers to the number of pixels along the total width and height of the image, known also as pixel dimensions. For example, if the pixel dimensions of a photo are 640 x 480, the image contains 640 pixels in its width and 480 pixels in its height.

The pixel dimensions, in turn, correspond to the image's file size. The larger the pixel dimensions, the more data (and therefore the larger the file size). Every image has a set number of pixels. How does it get these pixels in the first place? You establish the number by the capture setting on your digital camera or the resolution setting on your scanner (see the sections "Working with Camera Resolution" and Working with scanner resolution" later in this chapter).

To see the pixel dimensions and file size of an image in Photoshop Album, choose ViewOSizeOSingle Photo. The file size and pixel dimensions appear below the photo and also in the Properties pane, as shown in Figure 3-2. If your Properties pane isn't visible, choose ViewOProperties.

Figure 3-2:

Check out the file size and resolution of an image in the Single Photo view.

Figure 3-2:

Check out the file size and resolution of an image in the Single Photo view.

Size takes on two roles in digital imaging:

i File size: A result of the pixel dimensions just mentioned i Print or image size: The width and height of an image when printed on paper (described in the section "Working with output and printer resolution," later in this chapter)

The file sizes of raster images can be very large, in comparison to slim and petite file sizes of vector images. You may have discovered this fact on your own while working with your digital camera or scanner. It seems that in no time flat, that CompactFlash card, memory stick, or hard drive space is eaten up. Another disadvantage of raster images is that because they contain a fixed number of pixels, when they're enlarged the quality can go downhill fast.

Digital Cameras For Beginners

Digital Cameras For Beginners

Although we usually tend to think of the digital camera as the best thing since sliced bread, there are both pros and cons with its use. Nothing is available on the market that does not have both a good and a bad side, but the key is to weigh the good against the bad in order to come up with the best of both worlds.

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