I would learn the basics of the C language first. Can't do anything without that. There are lots of C tutorials on the web, including one's for this forum, and other programming forums with a C section on them.
If you just want to manipulate images, I'd use software designed just for that, (GIMP, Photoshop, etc.)
If you want to learn to do it in C, then I'd see what answers you get here, but also, Google it, because this is a specialty application. As I understand it, you need to get a library that works with your format of image files, after you learn the basics of C, and then work through an intro on using that library, and work your way up, from there.
I doubt if you'd want to do it all "from scratch", but that's always an option with C, and just my opinion.
See, Basiccally i want to process medical images using C language.
I know basics od C, but i havent study for image processing.
Can u suggest the sources from where i can get basics for image processing with C language?
I actually did help someone with this, a long time ago - multiple 2D X-Ray type images that all needed a bit more contrast.
Key thing was that the guy who wanted help knew the image format EXACTLY. You have to have that for every type of image you will be working with.
If you need to learn the image format, I suggest one of these:
1) Do a Google search for <name of format or extension> format. Lots of formats are kept on the net.
2) Get a really simple image file, and open it with a free hex editor. It may look like goobletygoop at first, but in time, you can start to make sense of what the file format is, from it.
Mostly, I'd work with #1 way, of course.
Your image array may need unsigned char's, signed char's, unsigned int's, signed int's, etc., so be sure to get that data type info that you will need, as well. You'll also want to know how all the characteristics of light, are handled in the image: colors, intensity, etc.
I can't tell you more, because I just did it that one time, and the poster requesting help, knew all the format info already.