File formats
An important consideration when designing
Web pages is to keep the files small in size to facilitate
quick downloading. For this reason, we use compressed image
formats in Web graphics. The most common compressed image
formats are JPEG (pronounced Jay Peg) and GIF (pronounced
Jiff or as in gift). After creating or editing an image
you should save it in one of these formats.
JPEG and GIF file formats will enable
delivery (over the telephone line) of maximum quality pictures
at minimum size, and therefore maximum speed (and minimum
telephone costs).
JPEG
JPEG stands for Joint Photographic
Experts Group. As the name suggests this is the best format
for displaying photographs and other images with variable
shading.
Variable
shading is the term used to describe the varying degree
of colour tints commonly found in photographs.
JPEG images are capable of displaying
24 bit colour, or 16.7 million colours. JPEG images can
be further compressed, but quality deteriorates as compression
is maximised. It is best to not further compress JPG graphics.
If you want a smaller file size, try reducing the size
(width and height) of the image.
GIF was developed by CompuServe and
stands for Graphic Interface Format. This format can display
images of 256 colours or less and is used primarily for
graphic content with sharply defined colours, for example,
logos. It is also used for line sketches.
An important feature of GIF is its
unique transparency utility. You can specify that any
colour in a GIF image is transparent. For example you
may have created a logo and would like it to appear without
any surrounding colour on the web document. You will then
set the image’s background colour to be transparent.
This feature is widely used in the World Wide Web. For
example, the image to the bottom left does not have a
transparent background and the image to the bottom right
does have a transparent background.
An animated GIF is several GIF
images composed into a single image which, when viewed,
appears to be animated. Software like GifAnimator (downloadable
at http://www.webutilities.com/ga
.) is used to create animated GIFs.
Where to find graphics
Graphics are freely available on the World
Wide Web. However, this in no way means that all graphics
on the Web may be used at will. Only the graphics at sites
offering free clipart are allowed to be used without permission.
Use a search engine and do a search on "free clipart".
You will see that there are many such sites. Here are just
a few examples:
Animation
Factory
Absolutely
Free Clipart (click on Clipart)
A1
All Free Clipart 
Most photographs on other Web pages are
subject to the usual international copyright laws. Since
you will be publishing your website in a public forum (the
Web) you cannot just take a photograph and use it. However,
if you write to the owner of the site and ask permission,
you are most likely to be given permission to use the photograph
in your site. In this case you would acknowledge this ownership
by indicating the website where you found the graphic and
that you have permission to use it.
To capture an image from a Web
page
Right-Click on the image
Choose Save Image As
and save it to a folder of your choice.
If you want to use it in a Web page, it is advisable to
save it to the same folder.
