  After thirty years of the GIF file format, today is becoming more popular
than ever: being a great way of communication for friends and communities on
Instant Messengers and Social Networks. While being so popular, the original
compression method to encode GIF images have not changed a bit. On the other
hand popularity means that storage saving becomes an issue for hosting
platforms. In this paper a parametric optimization technique for animated GIFs
will be presented. The proposed technique is based on Local Color Table
selection and color remapping in order to create optimized animated GIFs while
preserving the original format. The technique achieves good results in terms of
byte reduction with limited or no loss of perceived color quality. Tests
carried out on 1000 GIF files demonstrate the effectiveness of the proposed
optimization strategy.
