Infographic

Vector graphics
These use geometrical objects such as points, lines, curves, and polygons to form an image. Vector graphic files store the lines, shapes and colours that make up an image as a mathematical formulae.

Raster graphics
This uses a rectangular grid of pixels or points of colour, viewable via a monitor, paper or other display medium, unlike vector graphics there is a maximum amount of resolution a raster graphic can reach before it still start to pixelate.

A pixel is the smallest addressable screen element in  raster graphics.

Colour space is an abstract mathematical model describing the way colours can be represented as tuples of numbers (typically as three or four values). When defining a colour space the usual reference standard is the CIELAB colour spaces, which was specifically designed to encompass all colours the average human can see.

Bit depth is the number of bits used to represent the colour of a single pixel in a bitmapped image. High colour depth gives a broader range of distinct colours.

Optimizing is a process of optimizing pictures to balance between file size and picture quality. Saving in JPEG vs GIF will get you a better looking picture but will also make the file size bigger. This is why GIF is the preferred format for the web. Image will load quicker since the file size is smaller but a little photo quality is sacrificed.

Image capture is not possible without the use of a digital camera or a film camera. The technology behind a digital camera is a light sensor and a program which is embedded right into the circuit board of the camera. A Charged Coupled Device or CCD for short takes light energy and converts it to electrical energy. The firmware knows what each specific charge means and translates it to information that includes the colour and other qualities of the light that can ccd picked up. It does this using pixels. Each pixel comprised of three basic colours that can be produced is amazing indeed. This is known as a Bayer filter. Without this technology digital camera would never have existed and film cameras would still be common practice to date. Film cameras use similar principle to the human eye but exposes it to photographic film which stores the image. Without these two methods of capturing images, we would not be able to capture the beautiful pictures we do today.