Understanding Image Representation in Binary

What is the binary representation of a simple black and white image where 0 is black and 1 is white?

• Pixels

• Metadata

• Colour depth

• Resolution

Answer explanation

The binary representation of a black and white image is made up of pixels, where each pixel is represented as either 0 (black) or 1 (white). Therefore, the correct answer is 'Pixels'.

What does colour depth determine in an image?

• The number of pixels

• The range of colours

• The file type

• The resolution

Answer explanation

Colour depth refers to the number of bits used to represent the colour of a single pixel in an image. A higher colour depth allows for a greater range of colours, making the correct answer 'The range of colours'.

How many possible colours are available with a colour depth of 3 bits per pixel?

• 4

• 8

• 16

• 32

Answer explanation

A colour depth of 3 bits per pixel allows for 2^3 combinations. This equals 8 possible colours, making the correct answer 8.

What is the formula to estimate the size of an image file?

• Image height (px) + image width (px) + colour depth

• Image height (px) x image width (px) x colour depth

• Image height (px) x image width (px) + colour depth

• Image height (px) + image width (px) x colour depth

Answer explanation

The correct formula to estimate the size of an image file is: Image height (px) x image width (px) x colour depth. This accounts for the total number of pixels multiplied by the bits per pixel, giving the file size in bits.

If an image has a height of 200 pixels, a width of 400 pixels, and a colour depth of 16 bits, what is the file size in kilobytes?

• 80 KB

• 160 KB

• 320 KB

• 640 KB

Answer explanation

To calculate the file size, use the formula: height x width x color depth. Here, 200 x 400 x 16 bits = 1,600,000 bits. Convert to bytes (1 byte = 8 bits): 1,600,000 / 8 = 200,000 bytes. Finally, convert to kilobytes: 200,000 / 1024 = 160 KB.

What does the resolution of an image describe?

• The file type

• The colour depth

• How tightly packed the pixels are

• The date created

Answer explanation

The resolution of an image describes how tightly packed the pixels are, indicating the level of detail in the image. Higher resolution means more pixels per area, resulting in clearer and more detailed images.

What is metadata in the context of image files?

• The number of pixels

• Data about data

• The range of colours

• The file size

Answer explanation

Metadata in image files refers to 'data about data', which includes information like camera settings, date taken, and image dimensions, rather than just the image's pixel count, color range, or file size.

Which of the following is NOT included in the metadata of an image file?

• File type

• Author

• Colour depth

• Number of pixels

Answer explanation

The number of pixels refers to the image's resolution and is not considered metadata. Metadata typically includes details like file type, author, and color depth, which describe the file rather than its dimensions.

What happens to the file size as the resolution of an image increases?

• It decreases

• It remains the same

• It increases

• It becomes zero

Answer explanation

As the resolution of an image increases, the number of pixels also increases. Since file size is largely determined by the number of pixels and the color depth, the file size increases with higher resolution.

Which of the following is a key fact about digital images?

• They are made up of metadata

• They are made up of pixels

• They are made up of file types

• They are made up of authors

Answer explanation

Digital images are primarily composed of pixels, which are the smallest units of a digital image. Each pixel represents a color and together they form the complete image, making 'They are made up of pixels' the correct choice.