This document discusses different types of digital images. Raster images are made up of pixels and lose quality when resized, while vector images use paths and shapes so maintain quality when resized. It provides details on raster and vector images, comparing their advantages and disadvantages. Common file formats like JPEG, GIF and TIFF are also explained, including when each format is best used.

1. Raster and Vector Images

2. Digital Imaging Digital imaging is the use of images that can be
altered using a computer for varying outcomes. They
can be natural (such as a photograph) or artificial
(such as a drawing created on Photoshop). Digital
imaging is often used to communicate information.
Raster Images Raster images are created by altering the colour of
pixels and mapping them out, they are also called
bitmap images. Their quality is dependent on
resolution. They are manipulated by changing pixels
not shapes.
Vector Images Vector images are not made of pixels, instead they
are created using a series of paths. These paths can
be used to form geometric shapes and lines. They do
not loose quality when resized because both their
appearance and size are defined by algorithms.

3. Raster Image Vector Image

4. Advantages Disadvantages
Raster • Ideal for photos that involve
varying tones and complex colour.
• They are dependent on
resolution so it is hard to resize
• Can be used to store real world them without altering image
images, such as scanned quality
paintings • The file size can be very large if
• Raster formats translate well to the image contains many colours.
dot outputs, such as printers • Raster images do not scale well,
• Can be edited easily, either by shrinking the image removes
one individual pixel at a time, or a pixels while increasing the size
group of pixels. replicates pixels, in turn
decreasing the quality.
Vector • Can be used for 3D imaging
• Can easily be made larger or
• Cannot be used to store very
complex images
smaller without loss of image • The appearance of the image can
quality vary from application to
• It is a flexible file format, can application due to the individual
easily be changed into a raster application’s interpretation of the
image or another type of vector. image
• Reconstruction of the image can
take longer than a raster because
it’s elements must be redrawn in
sequence

5.  Graphic Interchange Format
 Gifs are mainly used for web
graphics, such as navigation
buttons.
 Can have up to 256 indexed
colours, because of this they
are relatively small files and are
easily transmitted on the web.
 Lossless image file format
 Can be animated (as seen in
the example) because of it’s
layered format.

6. Explanation When To Use This
Format
JPEG Stands for ‘Joint Photographic Experts Group’. A For photographs and natural
compressed file format. No colour limit. JPEG’s images, web use
have a lossy format. Raster image.
GIF Stands for ‘Graphics Interchange Format’. A Web use, small images, icons
compressed file format. Indexed colour, with a
maximum palette of 256 colours. Permits
transparency. Can be animated
TIF Stands for ‘Tagged Image File Format’. Storage and interchange of
Uncompressed file format. Can handle quality large files such as high
ranging from 1-bit to 24-bit. There are 50 definition photos.
variations of the format after it being developed in Can be customized to store
the 1980’s. A very versatile format. any peculiar type of data.

7.  http://www.techterms.com/definition/
vectorgraphic
 http://www.sharpened.net/glossary/definition/
jpeg
 http://www.sharpened.net/glossary/definition/
gif
 http://www.techterms.com/definition/tiff
 http://www.groups.esa.edu.au/course/view.php?
id=2882
