1. Picasso introduced the feelings of the artist into a portrait. Prior to that, artists painted exactly what they saw. Picasso painted what he felt like painting and how he wanted to: - a nose e.g. so he painted it from two angles - a face - the features he found most interesting.
2. Other artists took up this idea and began painting portraits which they felt expressed the personality of the person rather than just his exterior appearance.
3. For the reasons given above: very important
