Complete the indicated stories to unlock the corresponding image at the 'Gallery' menu.

A Lovely Singer: 'A Lovely Singer' story
Kiwi-Kiki in Danger: 'The Halloween Chase' and the 'A Lovely Singer' stories
Save the Earth: 'Save the Earth' story
The Aptitude Test: 'The Aptitude Test' story
The Halloween Chase: 'The Halloween Chase' story
Special Gallery: Successfully complete the game