DavidH64

Oh alright! thanks a bunch!

Great! You can replicate it, though why did you flag it as [resolved], as it clearly isn’t fixed yet?

Also, the permissions for the folders are 770 www-data:www-data and for the files, it is 660 www-data:www-data.

Yes, when the issue happened, i had all tools enabled, including optipng and pngout. upon disabling pngout, i had no longer one of these tmp.png files spawning.

Just to make sure its pngouts fault, I tested it again with just pngout running (no optipng) and it did spawn and keep the additional tmp.png files, even after they were all done.

I did some tests and noticed, that it does not always happen for all .png files within one folder, just some. I suspect that pngout crashes on the files for some reason and fails to remove the erroneous file afterwards?

Here is a copy of a file that does spawn a .tmp.png child when ran though pngout: https://a.loveisover.me/mquubm.png
Also, here is the .tmp.png copy of said file. Notice that the new .tmp.png file is smaller than the original: https://a.loveisover.me/ffnbmw.png

The RSS feed for me is also always empty, but that is probably just the result of the failed query…

Dunno what else to say…

I discovered the same error in my logs and discovered, by crosschecking the access logs, the following script is at fault: /wp-content/plugins/nextgen-gallery/products/photocrati_nextgen/modules/ngglegacy/xml/media-rss.php

So its the RSS feed of the plugin that is the cause of this php error.

My recommendation: Disable the RSS feed of the plugin, at least until its fixed.