Recently, we got a new digital camera. My hard drive is now filled with endless photos of my dogs. Of course, other dog-loving friends want to see some of my dog pictures, so I’ve been e-mailing photos to people. All of these folks will be looking at the pictures on their computer monitors, not printing them out.
You may wonder why I care whether or not someone is going to print my photo. (Yes, there is a reason!) To keep e-mail friends happy, you need to think about image resolution. A computer monitor can only show an image at a maximum of 72 or 96 dots per inch. Image resolution is related to image size. So if I send you that cool picture of my dog at 300dpi, it is likely to be about a 700K photo.
On a dial-up connection, 700K takes a while to download. A long while. It takes a lot less time to download a 70K photo, or even a 7K photo and it’s easy to change the size. You just need to go into your favorite image editing software. In Photoshop, to change the image resolution, you choose Image|Image Size. The command is called Resize in Paint Shop Pro.
To give you an idea how much of an impact resolution has on file size, here’s an example of a digital photo I just resized. The original was 780K and the resulting image is 26K. The original was 2272x 1704 pixels at 300 dpi. (That’s a lot of pixels, so no wonder it’s a big file!) I reduced the image to 400×300 at 72dpi.
In fact, I could have reduced it even more if I were going to use the image on a Web site. When you put images online, again you must consider how long it takes someone to download the image. Those people visiting a Web site on dial-up connections do appreciate small graphics!