How can I manipulate images in C++? Is there any built in function?
I googled and found that only bitmap images can be used, but why not jpeg and png and others ?
Is there any built in function?
No. There are probably image libraries that you can get, some free and others not free. I never tried to do that so I don't know.
You have to use an external library for this purpose. The "built-in" functions of C++ are limited by design (to make it portable to any system easily).
A good library for image manipulation is OpenCV (which is only Mac / Linux, as far as I know, EDIT: apparently they have Windows support now, this must be pretty new). Other options include FreeImage which is more minimal (load / save various image formats, and that's pretty much it). Also, most GUI libraries (Win32, MFC, Qt, WxWidget, GTK, etc.) include a number of basic image loading / saving capabilities, and some "canvas" system to draw and modify images.