Pixel (picture elements)

Color Depth

1 bit

8 bit

24 bit

32 bit

RGB vs CMYK

Mixing the colors created a new color.

Hex values in a web page for color. 000000 to FFFFFF

Color Palette and web palette (216 colors)

Web Safe Colors

Dithering colors

Steganography - Example

Bitmapped (raster) images

• Anti-aliasing

Vector Images

BMP - Bitmaps

GIF (Lossless) - Graphics Interchange Format

• Flat, limited colors, good for cartoon and illustrations

• Not good for real world images, or images of more than 256 colors.

• Indexed Color

• 87

• 89a

  • Animation

  • Transparency

• Interlacing

PNG - Portable Network Graphics

JPG (Lossy) - Joint Photographics Experts Group

• Photographs and images of mixed color patterns. Not good for cartoons or text.

• It tricks the eye by using less information for the image in hopes the user can not tell. It averages out the color information in parts of the image. Similar colors equals better compression, since there less information to store.

• Color example

• Progressive

DPI - Dots Per Inch (really picture elements per inch). Usually means pixels. Such as printers have say 600 DPI, but really it takes more than 1 dot to display 1 pixel. On a monitor the DPI changes depending on your monitor's physical size and screen resolution.

Image Reduction:

• Resizing

• Cropping

• File Format Change

• Color Depth Adjustment

• Reuse the images on your site, because caching the images helps the need to download again.

Get images into the computer:

• Scanner

• Digital Camera

• Clipart and image collections

• Draw it yourself