Reduce File Size - Speed Up Download Time

[Roscoe]

I'm trying to speed up the download of the graphics on a web page of mine.

I read, "The palette can then be further reduced for individual images by prunning the extraneous colors and forcing the "close" ones to conform. "

I have Paint Shop Pro 9. How would I remove the extraneuos colors, and how would I see what my pictures and graphics looks like in websafe (216 colors I read) only colors?

http://loriweb.pair.com/optimize.html
http://www.hwg.org/opcenter/newslett...ps/aug00a.html

Thank You,

Roscoe

[jyoung]

Welcome to TalkGraphics.

If you are just concerned about the size of the graphic, then why not let PSP do the work? When you are done with your graphic, click file - export then select either jpeg or png optimizer. Then play with the settings to get your desired result.

[Roscoe]

Joe,

But I am worried about file size, reducing file size is one of the main ways of downloading a file faster.

I learned that you can't reduce the number of colors with JPGs unless you convert a JPG to a PNG or Gif, but the conversion is not the same as an original PNG or GIF.

The color reducing is really only done with PNG and GIFs by choosing (in Paint Shop Pro) choosing the image tab and then "reduce color depth".

Roscoe

[steve.ledger]

Don't worry about 'websafe' colours. That's an old issue when there were still PC's and screens that had 256 colour systems.

You don't reduce colours from a JPG to make it smaller (data wise), you increase the compression ratio (reduce quality %) to an acceptable level before the compression causes too much damage to the detail (artifacts and mosquitos caused by high compression = lossiness)

75% quality setting - file size 6.2KB: A few mosquitos show around high contrast areas, but is generally acceptable for web photos.


45% quality setting - file size 3.8KB : mosquitos are clearly visible around high contrast edges and some banding appears with large areas of colour (sky)


20% quality setting - file size 2.3KB : Unacceptable quality

[Trev]

Firstly as you said graphics lets clarify Photos Need the 16 mill colours and will look bad as a 256 palliated image. Drawings logos etc rarely have a lot of colours unless you have used gradient fills after all how many of us had 256 coloured pencils in our drawing box.
The best way to save is to use the File Export Optimisers In the png Palliated setting you have a slider for reducing the colours from 256 down to 17 and a preview to see how the image has changed. It even informs you of the projected file size and download times. Gif is similar works the same way.

My customized workspace has these icons dragged on to the standard tool bar as there so useful.

[ss-kalm]

Lots of photo's are uploaded to the web as gif's, and are perfectly acceptable as 256 colours. This does not mean from a set 256 colour palette, but rather 256 of the colours in your photograph.

[steve.ledger]

Keith you are right, sometimes a photo as an 8bit gif or PNG can look ok for the web.
However more often than not these types are larger (data size) than a 75% quality JPG, so no download speed gain at all I'm afraid.

Although detailed photos can look ok as a 256 colour GIF, those which have a large graduated colour area, such as sky, will show banding when the 8bit file type is used.

8bit GIF - 19KB


8bit PNG - 19KB


24bit JPG - 75% quality - 6.2KB
http://www.talkgraphics.com/attachme...2&d=1214948468

[ss-kalm]

Just pointing out that photo's don't necessarily NEED 16 million colours.

[steve.ledger]

Agreed Keith - however in the context of the thread, the 75% quality JPG 24bit method is the better choice when considering the download speed of a web page with photos.

[ss-kalm]

Absolutely - if they are regular sized. If they are irregular crops with transparent backgrounds - I like to post head and shoulders views of people on some site I have done, without backgrounds - then a jpg won't do, and you have to choose between a small gif or a large png. Typically I've gone with the gif, and haven't had any noticable problems. The pictures are certainly good enough for websites.