Thumbs replaced by alternative tag

[ZenithRS]

I gotta say I'm having exactly this problem on a photoplog lite install that I'm evaluating at www.classicrallycars.com/photoplog

Thumbs will load OK, then on next load will be replaced by the alternative "image" tag. Following the "image" tag can give a permission denied. Then on next load of page that thumb maybe OK and some others will vanish. Then sometimes they're all OK.

I'm experienced with php and installs etc. Permissions are correct as far as I can see. safe mode is off.

This is under vb3.6.5 (as you can see on the site).

Any suggestions?

Quite like the script, but can't purchase until I can see this resolved.

Cheers

[ZenithRS]

Some screenies to show what I mean.
Content visible to registered users only.

a ctrl-F5 refresh gives...

Content visible to registered users only.

and another ctrl-F5 gives

Content visible to registered users only.

Got me stumped. The missing thumbs seem to momentarily appear, as if being produced out of the cache, before being replaced by the alt tag Image

Then sometimes I click the Image link and get the actual image, other times I click the Image link and get...

Content visible to registered users only.

And I got this simply by clicking on page 2 of the page index...

Content visible to registered users only.

[Morgan]

There is nothing in PhotoPlog that returns a 403 forbidden, permission denied, message, so it might be coming form an htaccess file on your server. As for the seemingly missing images, I was able to access the following images using the link in one of your screenshots:
Content visible to registered users only.
The only thing I can think of is that your server isn't happy with the images being run through GD for display. In the pro version, you can select whether to have the image links be static or dynamic, whereas the lite version only uses dynamic links. Unested, but to bypass GD use, in the PhotoPlog file.php file find:
Content visible to registered users only.
And afterwards add the following:
Content visible to registered users only.

[ZenithRS]

Thanks Morgan.

No effect with that edit though.

It's not just photoplog's images that get affected. The header gif of the site actually has the same problem on photoplog pages.

Viewing the source of the page of one of the images on the index page that goes missing, as an example, the image source is

http://www.classicrallycars.com/photoplog/file.php?n=48&w=s

Plugging that directly into the browser brings up a 300 pixel medium sized image. And yet photoplog is presenting 100 pixel thumbnails on the index. Why is photoplog sourcing the 300 pixel image? It's the same for the thumbnails that do display correctly... the thumb is 100 pixel, and yet the html src for the image put directly into a browser address is the 300 pixel image. There are no size attributes on the img tag. Is this correct behaviour?

I'm probably wrong, but can't help thinking this may have something to do with the problem.

Thanks again

[Morgan]

Check the difference between these two links:

http://www.classicrallycars.com/photoplog/file.php?n=48&w=s
http://www.classicrallycars.com/photoplog/file.php?n=48&w=s

Note one has an & and the other has an & only. The HTML source uses & but if you copy-paste that directly into the browser address bar, the & doesn't make sense so you see the default thumb size set in the ACP settings. This would not cause images to not show. As I was browsing your gallery, I also received a 403 error message. I don't think this issue is related to PhotoPlog. I think the reason the images don't show is that they are also being randomly 403'd and that's why you see the ALT text. Shoot your host an email and ask if they have implemented any type of "flood protection" to stop multiple server requests. PhotoPlog does not send any 403 pages, and right now I get a 403 on http://www.classicrallycars.com/ so this isn't PhotoPlog. Sorry.

[ZenithRS]

I'm on a dedicated server so have full access.

The site has no problems until browsing photoplog pages, and then these issues arise, even when navigating away from photoplog pages. The site never has an issue before entering a photoplog page.

Can you try navingating the site and avoiding photoplog and see if you get any 403's?

Point taken on the ampersand, my mistake.

I'll keep poking around and see what I can figure out. Thanks for your time anyway.

[Morgan]

Understandably, it seems like PhotoPlog is the issue, but nothing, zip, nada in the PhotoPlog code would send a 403 error message to the client. Try looking at your mod_security Apache logs: http://www.onlamp.com/pub/a/apache/2003/11/26/mod_security.html

[ZenithRS]

Morgan, you were on the right track.

mod_dosevasive is apparently the problem and it's a commonly installed module in shared hosting environments.

Added the following to the VirtualHost for the domain in httpd.conf, restarted Apache, and all seems OK now.

Content visible to registered users only.

I found this on a forum dealing with Gallery 2 which can exhibit the same randomly missing thumbs and 403 behaviour.

Cheers