3 Replies Latest reply on Aug 29, 2006 6:21 AM by Newsgroup_User

    the use of slicing an image

    giuseppe_craparotta Level 1
      Hello everybody, I'm building my first site and I have 2 questions about page weight.

      I've read that slicing a big image in pieces implies that the overall weight of the image reassembled in a table is going to be lower than the weight of the same image inserted as a whole in a single cell table.

      1) Would you confirm that? It doesn’t seem so to me: if I open IE and go to properties, the weight of the page resulting from the single cell table is of merely 403 byte - instead, the page resulting from a pluri-cellular table is 2650 byte heavy. What’s true and what’s false? What’s the use of slicing if after that the weight is higher??

      2nd question:
      In the right-bottom corner of the main window, Dreamweaver tells that the page weight is of 3k downloadable in 1 second. But how is this possible if the single images composing the table reach a weight of 11,5 kb?
      aren't “k” and “kb” two different ways to express the same?

      thanks so very much,
      Giuseppe
        • 1. Re: the use of slicing an image
          Level 7
          > I've read that slicing a big image in pieces implies that the overall
          > weight
          > of the image reassembled in a table is going to be lower than the weight
          > of the
          > same image inserted as a whole in a single cell table.

          Where have you read this? It's totally wrong. In fact the weight may be
          more than the weight of the single image.

          > 1) Would you confirm that? It doesn?t seem so to me: if I open IE and go
          > to
          > properties, the weight of the page resulting from the single cell table is
          > of
          > merely 403 byte - instead, the page resulting from a pluri-cellular table
          > is
          > 2650 byte heavy. What?s true and what?s false? What?s the use of slicing
          > if
          > after that the weight is higher??

          This whole approach is wrong - taking a single image, and slicing it into
          pieces which are reassembled on the page to make your web page. It's a good
          way to get a single page on the web, but it's a terrible way to make a web
          site. Your pages should use no more graphics than absolutely required -
          there should be mostly text and HTML/CSS color/border usages, and very few
          graphics.

          > 2nd question:
          > In the right-bottom corner of the main window, Dreamweaver tells that the
          > page
          > weight is of 3k downloadable in 1 second. But how is this possible if the
          > single images composing the table reach a weight of 11,5 kb?
          > aren't ?k? and ?kb? two different ways to express the same?

          That counter is pretty unreliable. Depending on which DW you are using, it
          may be completely wrong.

          Page weight (as experienced when you fetch a new page from the server) is
          composed of the weight of the HTML markup, the images on the page, and the
          externally linked files (CSS/js/Flash, etc.). DW does a questionable job of
          taking all of those into consideration.

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          Adobe Community Expert
          (If you *MUST* email me, don't LAUGH when you do so!)
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          "giuseppe craparotta" <webforumsuser@macromedia.com> wrote in message
          news:ed17q8$61p$1@forums.macromedia.com...
          > Hello everybody, I'm building my first site and I have 2 questions about
          > page
          > weight.
          >
          > I've read that slicing a big image in pieces implies that the overall
          > weight
          > of the image reassembled in a table is going to be lower than the weight
          > of the
          > same image inserted as a whole in a single cell table.
          >
          > 1) Would you confirm that? It doesn?t seem so to me: if I open IE and go
          > to
          > properties, the weight of the page resulting from the single cell table is
          > of
          > merely 403 byte - instead, the page resulting from a pluri-cellular table
          > is
          > 2650 byte heavy. What?s true and what?s false? What?s the use of slicing
          > if
          > after that the weight is higher??
          >
          > 2nd question:
          > In the right-bottom corner of the main window, Dreamweaver tells that the
          > page
          > weight is of 3k downloadable in 1 second. But how is this possible if the
          > single images composing the table reach a weight of 11,5 kb?
          > aren't ?k? and ?kb? two different ways to express the same?
          >
          > thanks so very much,
          > Giuseppe
          >
          >


          • 2. Re: the use of slicing an image
            Level 7
            On Tue, 29 Aug 2006 11:18:32 +0000 (UTC), "giuseppe craparotta"
            <webforumsuser@macromedia.com> wrote:

            > 1) Would you confirm that? It doesn?t seem so to me: if I open IE and go to
            >properties, the weight of the page resulting from the single cell table is of
            >merely 403 byte - instead, the page resulting from a pluri-cellular table is
            >2650 byte heavy. What?s true and what?s false? What?s the use of slicing if
            >after that the weight is higher??

            That one is false. Each image file has a header section that describes
            the image. One image has one header. That same image sliced into ten
            pieces has ten headers. Add to that the overhead of ten separate http
            requests and you have considerably more to download with the sliced
            image.


            > 2nd question:
            > In the right-bottom corner of the main window, Dreamweaver tells that the page
            >weight is of 3k downloadable in 1 second. But how is this possible if the
            >single images composing the table reach a weight of 11,5 kb?
            > aren't ?k? and ?kb? two different ways to express the same?

            The fact is that the indicated size is unreliable. In DW 8.0, it was the
            weight of only the html code. It was supposedly fixed in the 8.01
            update, but I still wouldn't trust it. I use
            http://www.websiteoptimization.com/ to check page sizes.

            Gary
            • 3. Re: the use of slicing an image
              Level 7
              Murray *ACE* wrote:
              >>I've read that slicing a big image in pieces implies that the overall
              >>weight
              >>of the image reassembled in a table is going to be lower than the weight
              >>of the
              >>same image inserted as a whole in a single cell table.


              slicing *can* be a used to lower the weight of an image, yes. But it won't happen by itself.
              You have to slice the image and optimize each slice cleverly in order to reduce the total size weight.
              For example if you have a large image showing a city street with a large blue sky above, you can
              slice the image so that the sky portion of the image is an individual slice. Since the sky is all
              blue and has no details, you can then optimize that slice with a very low quality (as a jpeg).
              The street will need a much better quality.
              The resulting image can look very good (if you do a good job), and weight much less than the image
              would have if you didn't slice it and had applied a high quality to the whole.
              Doing a good job at this implies that you understand the advantages of different compression
              settings (jpeg quality and gif and png) depending on different aspects of the whole image.

              >
              >
              > Where have you read this? It's totally wrong. In fact the weight may be
              > more than the weight of the single image.
              >
              >
              >>1) Would you confirm that? It doesn?t seem so to me: if I open IE and go
              >>to
              >>properties, the weight of the page resulting from the single cell table is
              >>of
              >>merely 403 byte - instead, the page resulting from a pluri-cellular table
              >>is
              >>2650 byte heavy. What?s true and what?s false? What?s the use of slicing
              >>if
              >>after that the weight is higher??
              >
              >
              > This whole approach is wrong - taking a single image, and slicing it into
              > pieces which are reassembled on the page to make your web page. It's a good
              > way to get a single page on the web, but it's a terrible way to make a web
              > site. Your pages should use no more graphics than absolutely required -
              > there should be mostly text and HTML/CSS color/border usages, and very few
              > graphics.
              >
              >
              >>2nd question:
              >>In the right-bottom corner of the main window, Dreamweaver tells that the
              >>page
              >>weight is of 3k downloadable in 1 second. But how is this possible if the
              >>single images composing the table reach a weight of 11,5 kb?
              >>aren't ?k? and ?kb? two different ways to express the same?
              >
              >
              > That counter is pretty unreliable. Depending on which DW you are using, it
              > may be completely wrong.
              >
              > Page weight (as experienced when you fetch a new page from the server) is
              > composed of the weight of the HTML markup, the images on the page, and the
              > externally linked files (CSS/js/Flash, etc.). DW does a questionable job of
              > taking all of those into consideration.
              >


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