The image you see on your TV or computer monitor screen is made up of small rectangular dots called pixels.  "Pixel" stands for Picture Element, and it's the smallest resolvable rectangular area of an image.  Actually, each pixel is itself composed of three close dots of color: red, green, and blue (RGB).  Combined together on the phosphor screen, the three separate colors appear to blend into a single color.

From a distance, each pixel ends up looking like a single dot of color. Look closely though, and you will see that each pixel is really three rectangles of red, green, and blue.  Most computer monitors use circular blobs of phosphor and arrange them in triangular formation (see diagram 1).

 Red, Green and Blue Pixels = RGB

RGB images (Gifs and Jpegs) are designed to be viewed on screens like this, and only require a low resolution (72 dots per inch, or dpi).  Phosphorous pixels glow.  This is why you tend to view a television from a good distance away, and why monitors make your eyes sore.

By comparison, printed images are often viewed closely, and are made up of pixels that do not glow.  Also, there are four colors: Cyan, Magenta, Yellow and Black (CMYK).  As a result they need many more dots, and finer dots, to convey an image smoothly.  The image below left (a Jaguarundi) is scanned from a National Geographic magazine.  Zooming in on the right pupil we see it is made up of very tightly packed dots, almost too small to see with the naked eye.

When you view a high-resolution CMYK image on a low-resolution screen, there is a conflict.  Your screen's large pixels can't display the tiny dots of the high-res image properly, and as a result, you may see jagged edges.  This is just an illusion, which you can prove by printing the image out.

Software

Which program are you using to view the image?  Some programs are not very efficient at viewing images, while others allow you to zoom in until the jaggies disappear.  If you are having problems viewing your images, be sure to let us know which program (and version) you are using to view.

Printers

Printers can also cause confusion, as they may not be able to print a high resolution image very clearly, if they are equipped with lower resolution output.  For instance, if you print a 600 dpi photo with a 300 dpi printer, the photo will appear dotty, or jagged.  This does not mean the image is dotty; it simply means you need a higher resolution printer.

AOL

If you're an America Online user, you may have noticed that AOL sometimes has trouble displaying Web graphics.  This is because AOL rarely shows an actual web page to its members.  Usually, it is a copy of the real web site.  Images are copied and their file sizes are reduced, which also reduces the quality.  If you use AOL as your browser and you would like to view the images as they were intended to be viewed, you should turn the graphics compression off.

AOL version 4.0 or 5.0

• Connect to AOL
• Click on "My AOL" …. it's on the top, in the middle … a menu will drop down
• Click on "Preferences" … a window will pop up with various options
• Click on "WWW" ... a window will come up displaying "Internet Options"
• Click on the tab that says "Web Graphics"
• You'll see a box next to the phrase "Use Compressed Graphics" … uncheck the box … click "OK" to close the window.
• Close the "Preferences" window by clicking the "X"

AOL version 3.0

• Connect to AOL
• Click on "Members" … a menu will drop down.
• Click on "Preferences" … a window will pop up with various options
• Click on "WWW" ... a window will come up displaying "Internet Options"
• Click on the tab that says "Web Graphics"
• You'll see a box next to the phrase "Show Uncompressed Graphics" … check the box … click "OK" to close the window.
• Close the "Preferences" window by clicking the "X"