Solution:
1. Modify php.ini
change memory_limit from 8M to 16M (or larger), restart the apache service
2. Add ini_set("memory_limit", "100M");
in the PHP fileNote: For the normal use of other system resources, please do not set the memory_limit too large, where -1 means no limit
3. Modify the .htaccess document (provided the directory supports .htaccess)
Add a sentence in the document: php_value memory_limit 16M (or greater)