No, just because it's cartoony wouldn't mean it was easy. Given that those all had the same style, those were drawn, not 'shopped. Of course, they could have been drawn in photoshop, but I doubt that would be the tool of choice.
They're beyond my skill level in Photoshop; that's half because I don't even use Photoshop.
I'd say the images were done in either a vector based program like CorelDRAW or Illustrator, or more likely using a cell shader with a 3D rendering program.
In 3D I'm more proficient at modeling things I see in the real world, but lacking in the creativity for much original content.