Lecture Summary 4
Prepared by: Anthony Larrain
Images
- Your web pages can display digital images.
- An image is a collection of pixels organized into rows and columns. Recall a pixel is the basic unit of an image on a computer screen.
- These numbers are stored in a file on your computer.
- There are many file types used to store an image. The two most common file types for the web are:
- JPEG (pronounced "jay peg") which stands for, Joint Photographic Experts Group, are files that end in .jpg
- butterfly.jpg
- tree.jpg
- GIF (pronounced "giff") which stands for, Graphic Interchange Format, are files that end in .gif
- tweety.gif
- sylvester.gif
- See HTML tutorial 8.
Think of it like this, an image is made up of many many dots. Each dot is called a pixel. Each pixel represents the smallest portion of the image in a particular color, or shade of gray. Since these pixels are so close together we see an image.
In computer graphics each color is made up by varying the intensity of the colors red, green and blue. So computer color is a composition of red, green and blue. When an image is digitized, these pixels are given numeric values. These numeric values describe the amount of red, green and blue in the pixel.
Examples:
Examples: