Binary comparisons like bigger/smaller and longer/shorter is an important skill, and is a building block to teaching "degrees of comparison" - today's free autism resource. Degrees of comparison include at least three choices - for example "big, bigger, biggest" or "short, shorter, shortest". It is a higher level skill, but one that requires executive processing, a great area of the brain to exercise for individuals with ASD.
To use this activity, simply cut out all of the objects in colored borders, and have your students tape or paste them into the correct spots on the two worksheets. Or, laminate and velcro the sheets for repeated use!