Stylization strength controls how much the style from the artistic style image is applied to the input photo. Set smaller to preserve more original photo details. Set larger to make style more intense.
Brush size (size of style patterns): affects the size of the style patterns reproduced on the stylization.
Foreground preservation controls how much the foreground objects are preserved during applying artistic style. Generally this should be higher for portrait rendering and smaller for landscape scenes rendering without specific foreground.
Geometry preservation controls how many borders of objects, displayed on your photo are preserved.
Set this to lower value for fuller and more vivid style expression. Set this to higher value if you want to preserve particular details of the foreground objects, such as faces, gestures, etc.
Smoothness of color change controls the smoothness of color changes on the stylization. More distant objects are smoothed more. Increase this value if you want to highlight the foreground objects by blurring background objects.
Account for distance is controlled by Less/more preserve foreground parameter - increase it, if you want more diverse smoothing for close and distant objects.
Artistic style is applied unevenly across the image. Foreground is less, background - more.
Style strength change controls how style strength changes across the image:
Colors controls color scheme of resulting stylization: