We have encountered a bug that causes AutoBlogged to terminate unexpectedly when trying to create a thumbnail for an image. When creating thumbnails, AutoBlogged calls the WordPress function image_resize which in turn calls wp_load_image which in turn calls the PHP function imagecreatefromstring. All of these functions have proper error handling code, however there is a bug that sometimes causes imagecreatefromstring to halt with a segmentation fault when processing an invalid image.

We do not know the exact details of when and where the problem occurs, but we do know that a number of bugs have been reported related to segmentation faults with imagecreatefromstring. Note that the problem occurs due to an error while processing an image which could mean an invalid image or some other problem. The image may display fine in your browser yet could still be causing the segfault in the GD library.

Unfortunately, being a PHP bug there is nothing we can do to fix this error and because it is a fatal error we cannot just catch it and move on. All we can do is recommend that you check your PHP version to make sure you have the latest release. Otherwise, the only other solution is if you encounter this is to manually skip the post with the invalid image file using the Filtering options to create a URL blacklist or Keyword blacklist entry.

Fortunately this problem is quite rare but we did want to document the issue.