How can I upgrade from Joomla 2.5 to Joomla 3

Versions 3.5 and above of the gallery work in both Joomla 2.5 and in Joomla 3.x. Therefore there are no extra steps that need to be done when upgrading Joomla 2.5 to Joomla 3.x. Please upgrade Joomla using Joomla’s updater and the gallery will work in Joomla 3 after upgrading.