[thelist] Retro 90s webdesign - speeding up large image downloads

Peter Brunone (EasyListBox.com) peter at easylistbox.com
Tue Jun 7 13:57:05 CDT 2005


	Also -- at least this used to be true -- specifying height and
width in the image tag will speed rendering.

-----Original Message-----
From: thelist-bounces at lists.evolt.org On Behalf Of VOLKAN ÖZÇELÝK

> Fortunately (or unfortunately as the case may be) I've never done 
> image-based development. So, I've got about 113k page of images and 
> I'm preloading some of them in a javascript. Are there any other 
> techniques for minimizing large image downloads?
> 

Caveat:
If you are not using mouse-over hover images, rollover image buttons
etc. Javascript preload will not decrease the download time.

Actually it will not decrease the download time,  will just affect the
perception.

Preloading will best work if you have a slide-show kind of a page.

The thing you can do might be to optimize the images: 

There is a considerable difference in size between a .jpg with %85
quality and the same jpg with %100 quality. However they will pretty
much look the same to an untrained eye.

Decrease the number of colors in your palette as much as you can.
Decrease the quality of your images as much as you can.

Use greyscale images wherever possible.

And split your images to chuncks. So that people will not have to wait a
very large image to load till the end of their lives.

Actually splitting the image increases the number of HTTP requests and
thus adds up to download time. However, psychologically people want to
see some progress on the page rather than staring at a blank white
screen for 10 seconds.

I don't have any other technique in my repository wrt image download
time optimization.

HTH,
Volkan.





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