I've decided to learn Photoshop. So far today I've learned:
Photoshop is a raster editing application and it manipulates pixels which have a fixed size.
The differences between Raster and Vector.
Raster graphics are also called bitmap. A bit is either on or off and mapped to the screen.
Raster graphics have limited scalability (depending on the resolution and dimensions).
Raster graphics have a fixed and "perfect" resolution.
Vector graphics aka Bézier Curve (named after French engineer Pierre Bézier).
Vector graphics are made up of points and use mathematics to calculate or draw shapes.
Vector graphics are infinitely scalable and will print nicely at 5% or 5,000%.