I have made several effects trying to transform photos in "painted by hand" like images.
Some of them are more realistic, others are more impressionist or unreal.
I show you above a landscape and two pictures made from it. First you see a more intrusive effect and bellow a more realistic one. The models are very different.
The quality of result depends on the math properties of the image, so, according to the image, it could be better to apply some paint effects instead others.