The difference between a recurve bow and other archery bows is that the string touches sections of the limbs of recurve bow when the bow is strung. The recurve bow has tips that curve away from the archer when the bow is unstrung. The second curve goes against the natural curve of the bow; thus, giving the bow greater energy.
A recurve bow stores more energy than a straight bow of equivalent size, allowing the arrow to cast further. The traditional longbow is roughly equal to the height of a person who uses it.
The bow shown in the image also has a set of stabilisers fitted - long rod and V-bars.