Image doesn't appear periodically till cache is cleared

What do you mean with "Image CAPTCHA stops working"? Is it the CAPTCHA image itself that is missing or is it the whole CAPTCHA widget (fieldset+image+question+textfield+description) that disappears? Or does the validation of a correct CAPTCHA response fails?

Are there other situations where it starts working again, beside clearing the cache with devel? E.g. waiting 10 minutes and trying again, using another browser/computer, restarting the webserver (if possible), running cron, ...?

Can you also describe your setup (localhost/shared host/dedicated host, linux/macosx/windows, apache, ....)?

I can confirm that this does not work either, using Drupal 6.15 and captcha version 6.x-2.1.

I've tried everything suggested on the other forums and bug references, including:

- removing leading and trailing spaces before <?php and at the end in all *.module files (core, contrib and custom)

- Cleared cache, sessions and tried multiple browsers

- Checked safe_mode and disable_functions to make sure they permit it

- Verified that php + freetype and gd are working (the image font rendering selection works fine in the captcha setup)

I've tried just about everything, but images for captcha just do not display at all.

What else can I try?

does the simple math challenge work: shows up, bocks wrong answers, let correct answers pass?

what does the URLs to the CAPTCHA image look like? Is you site live, and can you give me the URL so I can have a look?

Same issue here! Any info would be great!

At ajitaw in #5: please provide more info. For example: this thread is about the Drupal 5 version of CAPTCHA, but I doubt you are still working with Drupal 5.

Closing old/outdated issues for 5.x releases, which is officially unsupported now.

If this issue still exists for Drupal6 or Drupal7, please reopen (and update the version)

I added a captcha to a webform. No matter what I choose (recaptcha, math, image) the captcha appears for a little bit. But after a while, the entire captcha will disappear and my form will be completely unguarded, and you can submit the form. consequently I'm getting a ton of spam.

I read around about if you incorrectly fill out a form it triggers it to disappear. I tried every combination of incorrectly/correctly filling out the form/captcha.
I thought, maybe it was because I was doing stuff in the backend because it appeared as if if I deleted a person it would idsappear, so I just waited. and occasionally refresh a different browser where I was logged out. Eventually, it would just disappear on its own again.

If I clear the cache it fixes it again... temporarily.

These are the modules I have enabled:

Administration menu (admin_menu) 7.x-3.0-rc1
Chaos tools (ctools) 7.x-1.0-rc1
Calendar (calendar) 7.x-3.0-alpha1
Date (date) 7.x-2.0-alpha4
Date API (date_api) 7.x-2.0-alpha4
Date Popup (date_popup) 7.x-2.0-alpha4
Date Views (date_views) 7.x-2.0-alpha4
Devel (devel) 7.x-1.2
IMCE (imce) 7.x-1.4
Backup and Migrate (backup_migrate) 7.x-2.2
Colorbox (colorbox) 7.x-1.1
Entity API (entity) 7.x-1.0-beta10
Entity tokens (entity_token) 7.x-1.0-beta10
Nodeblock (nodeblock) 7.x-1.2
Save Draft (save_draft) 7.x-1.4
Rules (rules) 7.x-2.0-rc1
Rules UI (rules_admin) 7.x-2.0-rc1
CAPTCHA (captcha) 7.x-1.0-beta2
reCAPTCHA (recaptcha) 7.x-1.7
Google Analytics (googleanalytics) 7.x-1.2
IMCE Wysiwyg API bridge (imce_wysiwyg) 7.x-1.x-dev
Wysiwyg (wysiwyg) 7.x-2.1
Views (views) 7.x-3.0-rc1
Views UI (views_ui) 7.x-3.0-rc1
Webform (webform) 7.x-3.13
Webform Rules (webform_rules) 7.x-1.0

If I turn caching on, it appears to work fine. its been 2 days since I turned caching on, and its still up.

in #8:

If I clear the cache it fixes it again... temporarily.

in #9:

If I turn caching on, it appears to work fine.

I don't understand..
what kind of caches are you talking about? (browser cache, drupal page cache, drupal form cache, drupal settings cache, ...?)