Clear and regenerate album cache for single photo that is not showed as thumbnail?

I have a HUGE library running the latest phpAlbum with the Clear_White theme available at with family pictures. It runs on a QNAP NAS with somewhat limited hardware resources. After turning the PHP memory limit up to 256M I have been able to get it working pretty well. I have pre-cached all resized pictures and thumbnails using a recursive wget run. Most of the pictures and thumbs now show quickly and look good.

My problem is that a few photos don't show up as thumbs in the gallery index, even if they are shown in the setup->photos GUI and are available via a direct link This sample picture is taken with the same camera and settings as many of my other photos that are working (EOS 30D).

I have tried rescanning the directory structure several times. Tried to rename the extension from lower to upper case .JPG. I restarted my apache web server. I've cleaned the browser cache and even used different computers and browsers. Looked in the .cache.hdr file and it looks correct, the current time when the thumb was last modified. I also tried to delete the cache_thmb_Uploads_ZainabPyramids.jpg_160_70_false__.cache and cache_thmb_Uploads_ZainabPyramids.jpg_160_70_false__.cache.hdr files. They get recreated but the thumb don't show. Looking at the html source code generated to the browser, no picture is linked.

After many hours troubleshooting, I got the idea to copy a new file into the directory, rescanned and suddenly BOTH thumbs showed! Removing the extra photo and rescanning makes the script loop, apache goes on forever at 212MB memory and 95.8% CPU. Restarting apache and rescanning works, but no thumbs are shown in the affected gallery again. Back to the initial status... This can be repeated over and over.

I think it seems like I have some problem with generation of album-files. Seems like it sometimes don't detect changes in the data-directory and that it sometimes creates empty album-files because of the loop?! How can I see which albumxxx.php file belongs to which gallery? Is it possible to just delete that file to have it regenerated? Can I delete ALL files in the album-directory without affecting the photo cache? Is there any way to see WHY it got bugged? Is there any way to automate a search for other broken albums/pictures?

My cache directory contains 35342 files and 532MB, so I am very reluctant to clear the cache when this happens. It takes days to repopulate...

My php_info() is available at

Any help is warmly welcome!
Best regards

How to generate cache?

Hi Roger,

Can you explain me how to generate automatically the cache? If I clear the cache, it only generate when the image is viewed in the perticullar size. It is my understand that they exist 5 caches for every pictures (small thumbnail ,
medium thumbnail , original thumbnail, small picure, medium picture)

Is there a way to generate all 5 cache of all pictures contained in the entire main directory and sub directories.


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