Choose a theme
1
Open Themes
In Style, select Themes.
2
Choose a theme family
Select Dune, Monet, Plein Air, Contour, Still, Haze, or Linen.
3
Choose a background
Click a background tile, or click Random for a choice from all theme families.

Use a color
In Style → Colors, select a color tile.

Use a gradient
In Style → Gradients, select a gradient tile. To create your own, click Create gradient…. Set the Start and End colors, then adjust Angle.
Use a mesh
In Style → Gradients, click Random mesh. Click Save or Save to palette to keep the mesh before generating another one.
Use an image
1
Open Custom
Select Custom.

2
Import the image
Click Import image…. Choose an image file.
3
Select the image
Click the image tile under Your images.