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Pictures on the Internet use a standard
resolution or dpi (dots per inch) of 72.
When you are going to publish a picture for the web,
you need to first create a blank picture in your editing
software package.
Make sure the picture has a resolution
of 72 dpi and also has the exact dimensions
that you will be using when the picture goes online.
Getting the dimensions wrong in your HTML code will
cause the image to distort - so use the same dimensions
in your HTML code as the image actually is.
Drag the image you want to publish
onto the blank image you have just created and use a
'Uniform Scale tool' to make the image fit.
Uniform Scale ensures that when you
want to reduce the width of an image, the height reduces
in proportion which avoids distortion.
Now all you need to do is save the
image in the right format for the correct type of image.
There are two main web image file formats: JPEG (also
jpg) and GIF. The difference between them is in how
each interprets images and is very important when choosing
the right format to save in. The format can dramatically
affect the filesize. Basically for text and other block
colour images use the GIF format. For Photographs and
blurred images use JPEG.
When saving for instance an advertising
banner as a GIF, reduce the number of colours in the
GIF to as few as possible.
When saving a photograph in the JPEG
format, set the quality ratio to around 75%.
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