Image Storage

• What are bitmap images made of?

  Pixels arranged on a grid
• How is the quality of a bitmap image determined?

  By the total amount of pixels
• What happens when you scale up a bitmap image?

  Visible loss of quality occurs
• What types of images are most commonly bitmaps?

  Photos and screenshots
• How are vector images created?

  By following mathematical instructions
• Why are vector images usually smaller in file size than bitmaps?

  Because they don't store individual pixels
• What is a key advantage of vector images over bitmap images?

  Vectors can be scaled without quality loss
• What is the formula to calculate the file size of a bitmap?

  File Size = Resolution x Colour Depth
• How is the resolution of an image defined?

  Width in pixels multiplied by height in pixels
• What does colour depth represent?

  Bits used to represent each pixel's colour
• How many colours can be represented with a colour depth of 1 bit?

  2 colours
• How many colours can be represented with a colour depth of 5 bits?

  32 colours
• How many colours can be represented with a colour depth of 1 byte?

  256 colours
• What is the RGB colour model used for?

  To represent different colours using red, green, blue
• How many different colours can the RGB model represent?

  16.7 million colours
• If the height is 6 bits, what is the resolution for a width of 8 pixels?

  48 bits
• What is the file size in bits if the resolution is 48 bits and colour depth is 1 bit?


  48 bits
• How do you convert file size from bits to bytes?

  Divide by 8
• How do you convert file size from bytes to kilobytes?

  Divide by 1000
• What is metadata in relation to images?

  Additional data about a file
• What are common examples of image metadata?

  Height, width, colour depth
• Why is metadata important for images?

  It helps display the image correctly
• What are the differences between bitmap and vector images?

  • Bitmap images are made of pixels; vector images are made of lines.
  • Bitmap images lose quality when scaled; vector images do not.
  • Bitmap images are larger in file size; vector images are smaller.
• What are the steps to calculate the file size of a bitmap image?

  1. Calculate resolution: width x height
  2. Multiply resolution by colour depth
  3. Convert from bits to bytes (divide by 8)
  4. Convert from bytes to kilobytes (divide by 1000)
• What are examples of metadata for a graphics file?

  • Height and width in pixels
  • Colour depth
  • Resolution
  • Geolocation
  • Date created
  • Last edited
  • File type
  • Author details