[cairo] Help with images

[Sanjay Gupta]

Hi List,
I was having a look at using cairo for image manipulations,
but after going through the docs and samples provided
it seems to me that to work with images (say opening an image file)
we need to work with image specific backend. Is my observation correct
or am i missing something? All the sample provided, make a call to
libpng for
storing a image. Does the same hold for opening an image also?
How do we work with jpegs and other image formats.
Kindly excuse me if i sound naive. 
Any help is greatly appreaciated.
Thanx,
Sanjay