Image loading and saving

[Pavel Syomin <syomin radico ru>]

Hi all!

I'm writing simple OCR library and want to load (and sometimes save) 
images in widely used formats (TIFF, PNG, JPEG and so on). My library 
manipulates grayscale images with 1 byte per pixel and up to this day I 
use libtiff for loading and saving tasks. Now I want to add support for 
other formats and there is a question: what libraries can I use? I know 
about GDK-pixbuf, but it's support only RGB color space and don't allow 
to partially load images. I can't load whole image in RGB and then 
convert it to gray scale because of big memory footprint...

Any ideas?