pictures are to dark

[W.Smith]

LaFoto is right. There's still a lot you can do to the pix you took. I took the liberty of trying it out on the pic you posted. Here's the before&after. This took 'Auto levels', 'fill-flash', and 'USM'.

Of course improving the exposure in the first place is a preferable approach. Spotmeter your subject, and/or increase the amount of light on the background.