Is
Raster image which is also called a Bitmap image, is a way to show an image in
digital form.There are many formats that a Raster image uses, the main ones
are, BMP, GIF, JPG, PNG, TIFF and PSD.
When
using a Raster image when seen on screen it is converted to pixels. Each one of
those pixels is assigned a definite value which determines its colour. The
colours it uses are red, green, blue (RGB) colour system. If a value of 0, 0, 0
were given to the RGB value, the colour would be black, and the maximum number it
can go to is 256 for each colour.
Something
that may worth to note about Raster images, is that if you enlarge an image
from its original size, it loses quality and distorts the image and makes it
blurry.
When
saving a raster compressing the image comes into play when you want to save
space on your computer but keep the same quality of the image. Lossless and lossy
compression is terms which describe when compressing the image file, if all of
the original data can be recovered when the file is uncompressed. Lossless
compression keeps every single bit of information that remains after the file
is uncompressed. The Graphics Interchange File (GIF) is an image format that is
used on the Web which is a lossless compression.
But
with lossy compression it reduces a file by permanently deleting certain
information, mainly information that’s not needed. If the file is uncompressed
only bits of the original information is still there (although the user may not
notice it). Lossy is mainly used for video and sound, where certain bits of
information loss will not be detected by most users. A JPEG image file is
commonly used for photographs and other images that have a lot of information
in on the web, which has a lossy compression. When using JPEG compression the
creator can figure out how much loss that can be used and trade it to gain a
smaller file size with good quality.
A
vector image is made up of thin lines and curves which are called paths which
involve mathematical theories. To create a vector graphic you must use computer
software that is capable of doing so, they need to create wireframe type images
and each line needs to point to certain node positions, node locations, line
lengths and curves. Any of the lines or curves that are in the vector can all
be assigned colour codes. With the way a vector is formed it can be sized to
any scale infinitely without losing quality in the image.
The
most common type of vector is text, this is because no matter how big you make
the text, it will always look the same quality, no matter how big or small it
is.
A
different plus side to using vectors is the file size, because of the files way
of using mathematical descriptions and not using single pixels, the file sizes
are much smaller. Therefore making is simpler to put on the Web or transferring
it to other people.
A
problem with using vectors is they only seem to use file types that are native
to the program that has been used to make the vector. Which means not everyone
may have that program, therefore not being able to open the vector image. There
are many different file types, but the main ones that are used are,
Encapsulated PostScript (.EPS), Adobe Illustrator Artwork (.AI) and Flash
Authoring (.FLA).
Examples
of Vector Images are below:
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