This set of Web Technology Multiple Choice Questions & Answers (MCQs) focuses on “Choosing the Right Image Format”.
1. What are bitmapped images?
a) The images which are yet to be mapped
b) Static images on web
c) The images which are already mapped
d) The images which can be modified
View Answer
Explanation: Bitmapped images divide a picture into a grid of pixels and specify the color of each pixel individually. If you look very closely at your computer screen you may be able to see the pixels that make up the screen. There are several different bitmap formats; common ones include JPEG, GIF, TIFF, PNG etc.
2. Which of the following is not true which helps the website to load faster?
a) Resolutions at or less than 72 pixels per inch
b) More dots/pixels per inch than usual
c) Aspect ratio maintained
d) Same color maintained overall in the picture
View Answer
Explanation: The more pixels or dots per inch an image contains, the larger the size (in KB) of the file, and the larger the file, the longer it takes to transfer over the Web. Note that while you can easily save an image that is 300 dots per inch at 72 pixels per inch for the Web, you cannot simply increase an image from 72 pixels per inch to 300 dots per inch, because you do not know what color the 228 pixels that are missing from every square inch should be.
3. What is indexed color format?
a) Having two or more colors in a specific pattern
b) Having different colors at different indexes
c) Many pixels using the same color
d) Each pixel having a unique color
View Answer
Explanation: Many pixels having the same color is known as indexed color format. This makes GIF images more suited to graphics (where there are often areas of the same color — known as a flat color). This make them less suited to photographs.
4. How many colors does a black and white GIF have?
a) None
b) Two, black & white
c) Three, black & white with the border
d) Cannot say/depends
View Answer
Explanation: Even if your image looks as though it just features two colors, say a black and white line drawing, it may use many more colors. For example, if you have a line drawing where the edges have been smoothed out by the graphics program, your image will contain more than two colors, because the edges use a variety of other colors to make them look smooth.
5. Which of the following is not a drawback of dithering?
a) If you place a flat color next to a dithered color you will be able to see where the change occurs
b) It can result in some banding in colors
c) It might result in the same exact colors as preferred
d) Result might be that the smooth gradient now looks like a series of stripes
View Answer
Explanation: If the GIF needs to use more than 256 colors, then most graphics programs, when saving GIFs, will use a technique called dithering to better represent the extra colors. This means that they use two or more colors in adjacent pixels to create an effect of a third color.
6. In a transparent GIF, a pixel can be?
a) Opaque
b) Only on
c) Only transparent
d) Only off
View Answer
Explanation: However, in a transparent GIF each pixel is either on or off, opaque or transparent, there are no degrees of transparency. As a result, if you try to use it with curved corners, the corners may appear pixelated.
7. What is LZW compression?
a) No data is lost and therefore there is no loss of quality
b) A picture shrinking into small size maintaining the aspect ratio
c) A picture shrinking into small size according to user choice
d) compressing in a way such that no dithering happens
View Answer
Explanation: To make GIF files smaller, they are compressed using a technique called LZW compression, which scans rows of the image looking for consecutive pixels that share the same color. When it comes across pixels that are the same color it indicates that, from this point, x number of pixels should be written using the same color.
8. Which image format suits for storing and compressing images such as photographs that use a wide range of colors?
a) GIF
b) Animated GIF
c) JPEG
d) PNG
View Answer
Explanation: When you save a JPEG, you can usually specify by how much, if at all, you want to compress the image, which depends upon the image quality you want. Lossy compression might take place because the image format discards this data when the image is compressed, some of the data is lost and the original cannot be recreated.
9. How are PNG format images different from GIF format images?
a) The number of colors available for use in an image is expanded to two
b) They are supported more by web browsers
c) PNG are developed way earlier than GIF
d) The number of colors available for use in an image is not restricted, so any color can be included without losing any data.
View Answer
Explanation: A map (like the lookup table that indicates the color of each pixel in GIFs) is used to provide different levels of transparency for every pixel, which allows for softer, anti – aliased edges. All PNGs tend to compress better than a GIF equivalent.
10. In which case animated GIFs works best?
a) Containing large areas of flat color
b) Containing only one color
c) Containing as many color as possible for better frame shift
d) Containing black and white colors
View Answer
Explanation: Since when the image is compressed after the initial frame has been recorded only the pixels that have changed need to be stored with each subsequent frame. It is far less suitable, however, for photographic images because many more of the pixels change, resulting in a very large image.
Sanfoundry Global Education & Learning Series – Web Technology.
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