Bitmapped Images

How images are stored as a grid of pixels.

Think of it like: The Mosaic

Have you ever seen a tiled floor picture? That's a bitmap!

  • Pixels: The individual tiles.
  • Resolution: How many tiles you use (More tiles = sharper picture).
  • Colour Depth: How many different coloured tiles you can choose from.

Theory

Pixel: The smallest element of an image (Picture Element).

Resolution: Width x Height (e.g., 1920x1080). Higher resolution = better quality but larger file size.

Colour Depth (Bit Depth): Number of bits per pixel.

  • 1-bit = 2 colours (B&W)
  • 8-bit = 256 colours
  • 24-bit = True Colour (16m colours)

File Size = Width x Height x Colour Depth

Metadata: "Data about data". Stored with the file so the computer knows how to display it.

Examples: File Type, Date Taken, GPS Location, Camera Model, Resolution, Colour Depth.

1-Bit Image Editor

Stored Binary Data:
00000000...

Want more colour?

Explore how Colour Depth affects file size in our advanced tool.

Launch The Pixelator

Check Your Understanding

1. What is Colour Depth in an image?

2. If an image has a colour depth of 1-bit, how many possible colours can each pixel be?

3. Which of the following is NOT an example of automatically added image Metadata?

Numerical Exam Scenario (AO2/AO3)

1 / 3

"An old retro game has a sprite icon with a resolution of 10 pixels wide by 10 pixels high. It only uses 4 colours. The developer upgrades the icon to use True Colour (24-bit). Calculate the final file size of the upgraded icon in Bytes." (4 marks)