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CAPTCHA image not displaying
Closed, ResolvedPublic


Author: wikt.3.connelm

An anonymous IP reported that they were unable to see the CAPTCHA
image. Viewing the link provided I am able to see the image in several
browsers. They did not report their browser or platform. (I do not know if you
can determine that from logs...or if logs are even turned on for this one
subcomponent.) --~~~~

Version: 1.6.x
Severity: normal
Platform: PC



Event Timeline

bzimport raised the priority of this task from to Low.Nov 21 2014, 9:04 PM
bzimport set Reference to bz4816.
bzimport added a subscriber: Unknown Object (MLST).

They'll need to provide information.

Note that the captcha images won't display correctly if cookies are disabled.

jcb wrote:

Thanks - firewall was catching the 3rd party cookie and that fixed it.

There shouldn't be any third-party cookies, just same-party cookies. Can you show me
what the cookie looks like and what setting caught it?

wikt.3.connelm wrote:

I haven't reproduced this user's scenario. But I did add an extra warning at which has made the
complaints stop for now.

omniplex wrote:

Just commented on a related bug, it doesn't work
in some constellations even if cookies are enabled
and the browser supports PNG, a wild guess is "file
name issue", the URL is ..."&wpCaptchaId=123456789"
without file extension PNG or whatever it is.

Because I cant load a single exemplar I also can't
check if something's unusual in its HTTP header.

No information provided. Closing as WORKSFORME

gangleri wrote:

screen dump - eu.wikipedia - captcha image not displayed - 01.jpg

screen dump from

c) Konqueror 3.5.5 (Using KDE 3.5.5)
on KDE version 3.5.5; System: Linux; Release: 2.6.22-gentoo-r2; Machine: i686

it works on

a) Mozilla/5.0 (X11; U; Linux i686; de; rv: Gecko/20070427 Firefox/ on Linux KDE 3.5.5
b) Opera see configuration at
all on KDE version 3.5.5; System: Linux; Release: 2.6.22-gentoo-r2; Machine: i686

the same happens at

the captcha image is visible for about three seconds and then disapears

best regards Reinhardt [[user:Gangleri]]


screen_dump_-_eu.wikipedia_-_captcha_image_not_displayed_-_01.jpg (858×1 px, 141 KB)

gangleri wrote:

REOPENing this bug

comment #7 is quite st*pid. Should a hint abpout using another browser should be added when captcha is used?

I do seem able to reproduce this with Konqueror 3.5.8 on Ubuntu Gutsy.

The image nearly always disappears (replaced by a tiny generic file icon) after something causes it to redraw, such as dragging a section over it or scrolling down, then back up.

I haven't been able to reproduce the problem on my local MediaWiki install, however, so there may be some sort of difference in the caching headers or some other behavior triggering it.

Seem to have fixed this in r30900.

Made two changes:

  • An explicit cache-control header allowing private caching. (No effect, but seems wise to have.)
  • Commented out the 403 Access Denied on subsequent loads of an already-viewed captcha image. This allows Konqueror to reload the image (god knows why) without losing it, so it doesn't disappear.

Since the image references are tied to the session, this _probably_ doesn't weaken the captcha much. But it'd be nice to know why Konqi is doing this crazy thing and how to stop it. :D