Continuing the discussion from Everything in my foreground disappears:
Drag a supported image file type into the SU workspace. Once the file is in, SU will want you to Scale it. The image can be converted to a texture by r-clicking on the imported image > Explode.
For your interest @generalrialki
Importing 2D graphics as textures
Paint Bucket Tool
Position Texture Tool
Creating texture tiles with Make Unique Texture
Creating Seamless textures for use in SketchUp