gistfile1.c

            char *dest = (char*) malloc(width * height * 4 * sizeof(char));
            short *subscript = (short*) imgData;
            for (size_t i = 0; i < width * height; ++i) {
                unsigned short x = subscript[i] + 1000;
                dest[i*4] = x >> 8;
                dest[i*4+1] = x;
                dest[i*4+2] = 255;
                dest[i*4+3] = 255;
            }
            
            FILE *fp = fopen("/Users/dennda/Desktop/binary.buf", "wb");
            size_t count;
           
            if(fp == NULL) {
                printf("failed to open sample.txt\n");
                assert(0);
            }
            count = fwrite((const char*) dest, sizeof(char), width*height*4, fp);
            printf("Wrote %zu char. fclose(fp) %s.\n", width*height*4, fclose(fp) == 0 ? "succeeded" : "failed");