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Some png-images lock up computer
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Description

Author: fred_chessplayer

Description:
When accessing the URL above, my browser uses 80 - 90% CPU -- and 400 MB RAM!

This was tested with both Firefox and IE 6.0.

The images used on the page are originally very large, cirka 8 MB when in full.
However, on my test page they are thumbnails.


Version: 1.5.x
Severity: normal
URL: http://commons.wikimedia.org/wiki/User:Fred chessplayer/Test

Details

Reference
bz4304

Event Timeline

bzimport raised the priority of this task from to Medium.Nov 21 2014, 9:00 PM
bzimport set Reference to bz4304.
bzimport added a subscriber: Unknown Object (MLST).

robchur wrote:

The server is still having to turn those 8MB images into 300px thumbnails, and
it's obviously choking on it; increased wait time - browser is hanging around.

Server side scaling of very large png and gif images was disabled a while back,
because it used too much CPU and made wikipedia slow. Thus, it is left to your
browser to scale the images. Which obviously takes some RAM and CPU, as well as
quite long to download.

I.e., this is not really a bug, it's a feature... of sorts. I hope we'll have
enough computing power soon so scaling of big images can be turned back on.

Actually, the cost of scaling such images could be reduced by re-using big
thumbnails - i.e. to create a 180x180 thumb, don't use the 3000x3000 original,
but the existing 600x600 thumb, etc.

dbenbenn wrote:

It would be nice if we could get a Special page listing all the overly-large PNG
and GIF images. I'd be willing to upload hand-scaled versions of those images
if I could find them.