Very Large Pictures

NZ_Kiwis

I'm creating a page which will show lots of photos, easy enough but these photos are 5000px x 3000px in size.

is there a quick way to load, display them so there is not a download delay?

cretaceous

um.. how can you show it unless it gets downloaded?
I assume you don't want to show thumbnails first...

progressive jpegs were meant to help on this, but IE still downloads it all before displaying

NogDog

I've not had occasion to use it, but I know there are some JavaScript (probably AJAX) methods out there for preloading images. This would assume some sort of web page where, for example, while viewing the first image, there is a "next" button of some sort that would load the next image in a sequence. You could then use the preload JS method to download the image while the user is still looking at the currently displayed image.

Of course, this does nothing to help the initial access to the page if the user does not already have that first image in his/her cache.

NZ_Kiwis

When you use GD to resize images, down the browser download the entire image?

cretaceous

whatever you see on screen is, by its nature, downloaded
so to see an image that size it must be donwloaded - by definition - to the browser

you could show low res approximations at ultra high compression
but that is what thumbnail is - it's a small version

whether you use GD or other image library makes no difference
- you just get smaller images that must also be downloaded

(fractal compression never did take off, did it.. that may have been a solution)

NZ_Kiwis

Sorry I should have been more clear, I mean if I use GD to create a small thumbnail, then is it being downloaded or is the server doing the work server side to read the image and coping it?

Weedpacket

Since GD runs on the server, it's the server running GD.

If GD creates a small thumbnail, and the browser downloads it, then the browser downloads the small thumbnail.

Weedpacket

cretaceous;10992089 wrote:
(fractal compression never did take off, did it.. that may have been a solution)

(a) tight proprietary control of the format preventing open development, (b) all the best results were hand-crafted (c) automated generation involved huge amounts of analysis for comparatively little perceptual gain.