Graphics

For bitmap images uncompressed, each pixel must be stored. Fore each pixel the colour value is stored.
The size of an image therefore is the total number of pixels, multiplies by the number of bits.

Resolution = 640*480 = 207 200.
Colour depth = 16bit (66 536).


Image filesize = resolution x colour depth = 307 200 8 16 = 4 915 200 bits. 


Divide by 8 to get bytes (B) = 614400 bytes.
Divide by 1024 to get kilobytes = 600KB. 

Anti-Aliasing

Used to smooth jagged edges, Dithers the colours around the edge.

Bitmap Applications are an image format suited for creation of Photo-Realistic images or complex drawings.


Two kinds of Complression: Lossy and Lossless

Lossy loses information upon decompression.
Lossless retains the image quality.

GIF - Graphics Interchange Format .GIF.

Characteristics
Supports only 256 colours (8 bit)
Can show transparency
Can be animaged.
Uses lossless compression.

Uses
Used extesnsvily on the web, Used predominantly for line art such as cartoons.

JPEG
Supports true colour (24bit)
Cannot show transparency or animation.
Uses lossy compression.

Use
Used extensivly on the web.
Used predominantly for photo realism.