Image Formats Quiz

Which of the following file-formats has poor image quality when enlarged?

• JPEG

• Adobe Portable Document Format (PDF)

• Scalable Vector Graphics (SVG)

Answer explanation

JPEG has poor image quality when enlarged due to its lossy compression, resulting in pixelation and artifacts.

What are vector images?

• Images that use coordinates and geometrical shapes to define an image.

• Images that use an organised grid of coloured squares.

• Images that are black-and-white.

Answer explanation

Images that use coordinates and geometrical shapes to define an image.

How are images displayed?

• As a matrix of 0's and 1's

• As a grid of pixels

• As a matrix of binary values

Answer explanation

Images are displayed as a grid of pixels, not as a matrix of 0's and 1's or binary values.

What is colour depth?

• The number of bits used to indicate an image.

• The intensity of colour at each pixel.

• The number of bits used to indicate a pixel.

Answer explanation

Colour depth refers to the number of bits used to indicate a pixel, not an image or the intensity of color at each pixel.

How many different colours does an n-bit system represent?

• 2^n different colours

• 2n different colours

• n2 different colours

Answer explanation

In an n-bit system, each bit can represent 2 different states (0 or 1). Therefore, with n bits, there are 2^n different combinations, which translates to 2^n different colours.

Look at the images given below. What is the difference between these two images?

• Colour depth

• Resolution

• Number of pixels

• Height and width of the image

Answer explanation

The difference between the two images is the colour depth, which refers to the number of bits used to represent the color of a single pixel.

Look at the images given below. What is the difference between these two images?

• Resolution

• Colour depth

• Height and width of image

Answer explanation

The difference between the two images is in their resolution, which refers to the number of pixels in the image. Resolution impacts the clarity and quality of the image.

Estimate the size of an image with: Height: 510 pixels Width: 402 pixels Colour depth: 16 bits

• 0.41 megabytes

• 0.41 bytes

• 0.41 gigabytes

Answer explanation

The size of the image can be calculated by multiplying the height, width, and colour depth, then converting to megabytes. (510*402*16)/(8*1024*1024) = 0.41 megabytes.

Which of the following statement is TRUE about colour depth?

• As the colour depth increases, the file size increases.

• A 2-bit colour depth results in a black-and-white image.

• A 24-bit colour depth may represent millions of colours per pixel.

• All of the above

Answer explanation

All of the above statements about colour depth are true: increasing colour depth increases file size, 2-bit depth results in black-and-white, and 24-bit depth can represent millions of colours per pixel.

Which of the following represents the calculation for estimating the size of an image file?

• File size (bytes) = height (p) × width (p) × colour depth (bits per pixel)

• File size (megabytes) = height (p) × width (p) × colour depth (bits per pixel)

• File size (bits) = height (p) × width (p) × colour depth (bits per pixel)

Answer explanation

File size (bytes) = height (p) × width (p) × colour depth (bits per pixel) is the correct calculation for estimating the size of an image file.