Place your mouse pointer over the image after viewing it
Both figures are the exact same size. The creature appears to increase in size as it gets further away due to 'perspective'.
Perspective is evoked in this image by the pattern, and the lines on the wall.

Confused yet?

A vase or two faces?

A young woman or a sax player

A man's face or the word 'liar?

A rabbit or a duck?

Squares 'A' and 'B' are believe it or not the exact same colour. (click here for proof) .
If you still don't believe it, use a graphics program
to cut a section out of squares A and B and compare them.They are identical.

Both central circles are in fact the same size

Move your head up and down. watch the centre.