Help with slices

[lopz webforumsuser@macromedia.com]

Hi,
I have a few images some are gifs some are jpegs which I have optimized and now I want to put them on my website.

Problem:
Whenever I try to insert a slice in an attempt to decrease download times the file size of these images go bigger in the preview tab. My question is - does that mean that they will take longer to download? Or with the slices in place, will they download faster even though the file size has got bigger?

Thanks

[Craig Hartel]

"lopz" [email]webforumsuser@macromedia.com[/email] wrote:

> Hi,
> I have a few images some are gifs some are jpegs which I have optimized and now I want to put them on my website.
>
> Problem:
> Whenever I try to insert a slice in an attempt to decrease download times the file size of these images go bigger in the preview tab. My question is - does that mean that they will take longer to download? Or with the slices in place, will they download faster even though the file size has got bigger?
>
> Thanks
>
>
>

It's not a given that slicing images into smaller chunks speeds up
delivery time. You still have to deliver the same, or even a tiny bit
more bytes of images to the viewer's browser.

[url]http://www.google.com/search?&q=optimize%20slices%20fireworks[/url] is a link
to GOOGLE search results about slicing with Fireworks. Check out
[url]http://www.communitymx.com[/url] as well, and don't forget Macromedia's site,
which has a nice new section built just for Fireworks at
[url]http://www.macromedia.com/devnet/mx/fireworks/[/url]

Craig Hartel

[lopz webforumsuser@macromedia.com]

But Is it possible that after I have inserted slices in the image that the image will appear quicker even though the overall file size increase by a little?
or
if I see that the file size increases after inserting slices should I delete the slices?

[Linda Rathgeber]

Hi Lopz,

The things that will make the page load faster are limiting graphics to
one or two areas on the page, such as a header and a navbar, and using
HTML text instead of graphical text.

Best regards,
Linda Rathgeber
----------------
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Contributor *PVII Foundations* [url]www.projectseven.com[/url]
Co-author *Playing with Fire* [url]www.playingwithfire.com[/url]
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-----------------

[jhutchdub webforumsuser@macromedia.com]

Slices don't reduce file size. Slices chop up a large image into several smaller ones. Keep in mind this reduces only the physical size of the image, not the file size.

Why slices are used is to break up a large image into several smaller ones in order to make it look like the page is loading. Since some of the smaller files will appear on the page quicker than one large one.

When a image downloads it needs to get it all before it can be displayed. By slicing the images we create several smaller images, which means these smaller images will appear quciker than one large one and this makes it appear as if the page is loading quicker than it would with a large image.

In other words, we're tricking the end user into think the page is loading quicker than it really is.

The best way is to make sure you optimize images as much as possible and use the appropriate file type. JPEG for photos and image with backgrounds, GIFs for logos, butons, etc. Make sure you have have no pngs on the page as these are huge files. Especailly since Fireworks saves all it's native files as PNGs.

[Joey Durham]

Hi,

One thing to note is that larger slices will take longer to be viewable to
the user. Smaller slices will atleast give the user an indication of an
incomplete image that is still loading. It will appear quicker. The download
time is roughly the same. An example of that is a 400x400 px image. That
image must load completely before it is viewable. If you slice that 400x400
image into 4 slices then each slice will load one at a time and will appear
sooner then the one 400x400. And yes large file sizes take longer to
download.

Also, just a tip.... In general you do not want a web page to be over 70k in
file size. Unless you are targeting broadband users you can bump that up a
bit. But as long as you keep that in mind you should be good on any file
size questions you might have.

Hope this helps.

Joey
[url]www.ultraweaver.com[/url]


"lopz" <webforumsuser@macromedia.com> wrote in message
news:bjs9lc$67b$1@forums.macromedia.com...

> Hi,
> I have a few images some are gifs some are jpegs which I have optimized

and now I want to put them on my website.

>
> Problem:
> Whenever I try to insert a slice in an attempt to decrease download times

the file size of these images go bigger in the preview tab. My question is -
does that mean that they will take longer to download? Or with the slices in
place, will they download faster even though the file size has got bigger?

>
> Thanks
>
>

[Stéphane Bergeron]

"jhutchdub" [email]webforumsuser@macromedia.com[/email] wrote:

> Slices don't reduce file size. Slices chop up a large image into
> several smaller ones. Keep in mind this reduces only the physical
> size of the image, not the file size.

That is very innacurate. Slices are not used to "chop" larger images
into smaller ones, they are used to optimize and export sections of a
layout into the best format possible for the type of image underneath as
well as to recreate the layout in code the most efficient way possible.
Chopping a larger image into smaller ones is a very innefective method
of reducing global page size. It increases the total page size and total
load time because of all the additional HTML markup and additional calls
to the server.

> Why slices are used is to break up a large image into several smaller
> ones in order to make it look like the page is loading. Since some of
> the smaller files will appear on the page quicker than one large one.

It will only appear to load faster but the whole page will take longer
to load.

> When a image downloads it needs to get it all before it can be
> displayed.

Not with Progressive JPEGs. Those will first load very quickly with a
very low res version and will become clearer as more data downloads.
Progressive JPEGs are usually a little bigger than normal ones but they
are worth it IMO.

> The best way is to make sure you optimize images as much as possible
> and use the appropriate file type. JPEG for photos and image with
> backgrounds, GIFs for logos, butons, etc. Make sure you have have no
> pngs on the page as these are huge files. Especailly since Fireworks
> saves all it's native files as PNGs.

Not quite. *Native* Fireworks PNG files can be very large but exported
PNGs can be smaller than the equivalent GIF or JPEG and usually look
better. PNG support in browsers is unfortunately spotty at best,
especially with 24 abd 32 bit PNGs. The 8 bit category is more widely
supported so a good knowledge of one's site audience and browser usage
would be required to use them safely.

Stéphane Bergeron