how to encode:
numbers
characters
now, pixels

picture element

2 color bitmap. L x W / 8
because only need 1 bit per pixel

16 colors
2^4 = 16
so we need four bits for each pixel
four bits = 1/2 byte
300 across x 200 down = 60,000 pixels
so, 30 bytes are necessary

256 colors.
2^8 = 256
so, need 1 byte per 1 pixel
60,000

24-bit bitmap = "True color" = 3 bytes per pixel
180,000
store RGB values
16,777,216 possible values

this was for .BMP files that you do this kind of mult to find the size

hexadecimal specification of color
#99 ff 00

RLE
run-length encoding
http://en.wikipedia.org/wiki/Run-length_encoding

GIF uses LZW encoding, which is a different encoding scheme. specifics, you don't need to know

lossless compression - GIF
don't lose info

lossy compression - JPG
loses info every time you save

raster vs. vector graphics
http://en.wikipedia.org/wiki/Raster_graphics
http://en.wikipedia.org/wiki/Vector_graphics

http://en.wikipedia.org/wiki/SVG