This looks like ink splats that have been scanned in and used for balloons. This poster is very colourful which shows it is a happy film, and for families. The balloons tell us the film has an uplifting mood and pace.
I cried every time when I watched this movie(I am the drama king and you know it haha). I have to Toy Story series made me think of the value and memories of my childhood. The brutal world took away our imagination, our innocence, and our pure happiness to make us capable of surviving.