Regarding IMGLIB functions usage with openCL

Hi All

I am trying to integrate IMGLIB with OpenCL and run IMG_sobel_7x7_16s program to do some processing of the image.
Using GPEVM (TMDSEVM572x) with ti-processor-sdk-linux-am57xx-evm-02.00.01.07-es2.0.
I am able to successfully allot the buffers, compile the program and load the kernel on the DSP(along with imglib.ae66).

But the buffers i am passing right now are empty. Now i want to pass some 640X480 image to this function:

From user manual all i can get is :

void IMG_sobel_7x7_16s     (    const short *restrict     in,
        short *restrict     out,
        short     cols,
        short     rows
    )

Now if i have jpg/bmp/tiff or any other format file. How can i pass that file to this function as input? In which format does it expects the input ? and what is the output format?
Please guide me, i am new to this DSP and image processing.

Thanks & Regards
Amrit