Having finally learned the difference between the two in my digital design class, I will attempt share my knowledge with those also technologically challenged. Please /msg me with errors.
Vector based programs (such as Adobe Illustrator) are based on points - coordinates that the computer remembers. Essentially, the program requires only certain points of information to produce an image:
- Location of key points (or coordinates)
- How those points are joined (whether with a straight line, or how much it's curved, etc.)
- Attributes, such as the colour of lines or the fill colour of the closed shape
Rastor based programs (such as
Adobe Photoshop) "remember"
all of the information for
every coordinate. This makes for a much larger file size.
When dealing in vector based programs, you can make the image infinitely larger or smaller without affecting the quality of the lines. The computer requires the same information for a very large image as it does for a very small one - and uses that information to produce the rastor image you see on your screen. But in rastor based programs, the program is suddenly missing information when the file is enlarged - creating a jagged, bitmapped, pixelated image.
This is essentially the key difference between Photoshop and Illustrator and is why the programs are used for different purposes.
Thanks to Wharfinger for editorial fine-tuning