There is a distinct halo around both of them, usually caused by excessive post processing, and the boy looks like he is picking his nose. I like the composition though.
The balance of the foreground and background child does very well in this image.
The viewers eye strikes the middle child, works it way to the right child, then searches for the object they are looking at ... the same path that the background hill takes.
For you Beginners ... this is what we would refer to as good composition ... all parts of the image are working together and form something greater than the sum of their parts.