Colour smoothing / Painted look

[_ck]

Hi All, I've attached a couple of pictures below where the colours in it have a very 'smoothed' gradated look, almost as if the picture could have been painted or drawn with pencils.

Does anyone know how this effect is achieved, or perhaps what this effect/technique is called so I can do a search online for it ?

In the third picture below, I'm particularly interested because it's not just blending a single skin tone, but various colours (I note the red patches on his face). This also seems to have been accomplished without loss of detail or skin texture in this particular photo.