Scaling IMG

[Roy Schestowitz]

Er... what? How does making visitors download a larger image than
necessary save bandwidth? Seems to me like it wastes it.

What I had in mind is resizing of images on the server. Instead of uploading
different versions of the same image (which in itself is extra traffic),
the server can detect the connection type and send images depending on the
connection speed. It's like an adaptive net that tailors content for the
visitor. Some will say it's a horrible idea, a little bit like cloaking or
like Micro$oft's delivery of different stylesheets to different browsers.

Roy

 

[Roy Schestowitz]

Huh? Are you saying that a graphics program is not ideal for the job of
resizing images, but using HTML and CSS to do that same job is?

Boy, does that sound backwards!

I just think it would be nice to add some directive in the code which
resizes images (properly). This saves a process of download, modify and
upload. Take Gallery for example (a popular PHP image gallery package):
rather than rotating images before uploading them, you are able to do some
on-line. I think that's an excellent feature.

Roy

 

[Jonathan N. Little]

Then do it server-side with PHP and GD2.




Who cares? What's LaTeX got to do with your question?

If you cannot resample beforehand then as Hywel says some server-side
processing is the way to go. Although your best control for 'sharpness'
and best quality control is done with image processing Photoshop and
kind. Scaling with constraining html or css IS NOT the way to do it and
for most browser the 'rescaling' algorithm just tosses out pixels and
degrades the image aside of the extra bandwidth. Here is a good example
what NOT to
do...

http://www.kiis.org/xkiis/index.php?option=content&task=category&sectionid=3&id=84&Itemid=26


Yep, 321 x 242 image is a whopping 1360 x 1024 GIF at 909Kb! If they had
resampled and used JPG it would have been a mere 16-14Kb image. There
are other page on this lousy website with images almost 2MB!

 

[Oli Filth]

What I had in mind is resizing of images on the server. Instead of uploading
different versions of the same image (which in itself is extra traffic),
the server can detect the connection type and send images depending on the
connection speed.

I can't think of a way that one could identify the user's connection
speed/type from the server...

It's like an adaptive net that tailors content for the
visitor. Some will say it's a horrible idea, a little bit like cloaking or
like Micro$oft's delivery of different stylesheets to different browsers.

In a way, yes! What if the user on a slow connection happened to *want*
the higher quality image?

 

[Frogleg]

I have had little success explaining to people, who send overly large pics
for screen viewing on dialup, the difference between file size and image
size. The relationship is intertwined but your use of the concept of
"weight" is very nice indeed and I will try it - with your permission of
course...

I agree. It drives me nuts (with dialup), to d'load a page of 80k
thumbnails. "Weight" is a good slant on the issue.