Images
Image Formats
Image Formats |
Creating Images |
Changing Format |
Transparent Backgrounds |
Background Tiling |
Animated GIFs |
Image Resources |
Screen Captures |
Going Further
Browsers
generally display images in two different ways: (1) in-line,
using the browser itself, and (2) externally, in a separate
window, sometimes with the aid of a "Helper Application".
The adjacent figure is an example of an in-line image; here
is an example of an external
image.
Image files come in a variety of formats, but most Web browsers
support only two or three of the formats for in-line images.
Thus, you may often need the capability to convert easily
among the various formats.
Displaying In-Line Images
The popular browsers support only a limited number of
graphics file formats for in-line images, with the most
common being GIF and JPEG. For graphics created on a PC,
files can often be saved in a BMP format, but sometimes
the software will not let you save the work as GIF or JPEG.
(This restriction was more common a few years ago than it
is today.) You don't need to worry about the technical differences
between BMP and JPEG and GIF formats; you only need to know
that there are programs available that will convert from
the BMP format to either GIF or JPEG.
Displaying
External Images
Web browsers are more flexible in the formats they can
display as external images because these are often displayed
using separate "Helper Applications" that can be tailored
to deal with a particular format. Provided a program exists
(and runs on your computer) that can display the format,
it is likely that the browser can be configured to display
that format by launching the helper application.
For example, it is very common in scientific and technical
settings to encounter images written in Postscript
format. (Postscript files commonly have a .ps or .eps extension
in their names.) A browser like Explorer cannot display
Postscript directly, but it can be configured such that
when it encounters a Postscript file it launches a helper
application that displays the file in a separate window.
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