Gallery3:Requirements

From Gallery Codex

Minimum System Requirements

Platform: Linux/Unix

Web Server: Apache 2.2 and newer

PHP: 5.2.3 and newer.

• PHP's safe_mode must be disabled and simplexml, filter, and json must be installed.
• PHP must have mbstring extension installed.
• short_open_tag must be On. See php.ini directives.

Database: MySQL 5 and later

Browser: Flash is required for the simple file upload function (Add > Add Photos).

Recommended Requirement

PHP Memory Limit: 32M should be the minimum for PHP's memory limit if you're restricted to using GD as your image toolkit. Processing images with GD eats into PHP's allotted memory and can get consumed rather quickly with even smaller images.