In article <sl*********************@bowser.marioworld>,
Ben C <sp******@spam.eggswrote:
On 2007-08-04, dorayme <do************@optusnet.com.auwrote:
In article <sl*********************@bowser.marioworld>,
Ben C <sp******@spam.eggswrote:
What's the point though, why not just use one big image? Is the idea
that over a slow connection you will see the image appear in slices?
As I understand it, slicing was partly touted as a way of
reducing file sizes because some parts can be more compressed
than other parts without unduly compromising the overall look.
Unless you manually make the compression more lossy for some slices,
slicing is always going to make the total bigger. Each slice will need
its own headers and in general compression works better the more data
you give it to work with at a time.
Of course, that is the idea, you are right, manually. Otherwise,
it would have to be a pretty clever program to know what was
important in a pic. I am not, of course, endorsing the
practicality of it. When it comes down to it, it is almost never
worth the bother.
>
[...]
I usually prefer to prepare pics as progressive loading, so they
appear sharper and sharper with each "pass" for the slow
connections.
Yes, that used to be done quite often. The downside is that a
progressive jpeg is a bit bigger in total file size and slower to load
completely.
Not bigger but smaller in my experience and practice. As for
slower loading to finality, I take your word for this and must
schedule some experiments to see for myself sometime.
The other motivation I might mention about slicing is to
introduce a bit of actual html text into the pic area. It is
mostly a ghastly thing to do, but a few clicks either way of text
upping or downing can be not too disruptive in certain types of
largish pics (the pic remains the same, the slice behind the text
being specially prepared to have the expected background of that
part of the picture, the text is slightly easier to read within a
narrow range). This is an accessibility argument. I do not
endorse it.
--
dorayme