The Web supports few raster file formats: JPEG,
GIF, and incomplete support for PNG. Other formats require use of a specialized
viewer, such as a plug-in, applet, or some other external application.
This limitation tends to dampen use as it places more demand on the user's
end. In some circumstances, the value of the format is sufficiently compelling
to overcome user resistance, as is the case with PDF files. Adobe lessens
user constraints by supplying a browser plug-in with its PDF reader. If
the stand-alone Acrobat Reader is already available when the browser is
installed, most will self-configure to launch it when a PDF file is encountered.
Some institutions convert non-supported formats or compression schemes
on the fly to ones that are Web-supported (e.g., wavelet to JPEG) in response
to user request.
probably care most about speed of delivery, as noted earlier.
Several variables control access speed, including the file size, network
connections and traffic, and the time to read the file from storage and
to open it on the desktop.