Recover - round 2

#include <stdio.h>
#include <cs50.h>

int main(int argc, char *argv[])
{
    // ensure proper usage
    if (argc != 2)
    {
        fprintf(stderr, "Usage: recover imagefile\n");
        return 1;
    }

    // remember filenames
    char *imagefile = argv[1];
    bool control = true;
    //bool jpegfound = false;
    int imagenumber = 0;
    char filenamestring[50] = "000.jpg";
    bool writingjpg = false;
    //int secondimagecount=0;
    //char buffer[4];

    //we only open this guy up once.
    FILE *fileinputpointer = fopen(imagefile, "r");
    //FILE *outptr = fopen(filenamestring, "w");//making an assumption 1 or more jpeg headers will be found. In this non-real world example, this assumption is justified.
    FILE *outptr;
    if (fileinputpointer == NULL)
    {
        fprintf(stderr, "Could not open image file %s.\n", imagefile);
        return 2;
    }
    while(control)
    {
       unsigned char buffer[512];//re-initialize as blank

        int bytesreturned = fread(&buffer,512,1,fileinputpointer);
        //if(new header found and imagenumber > 0)
        if(buffer[0] == 0xff && buffer[1] == 0xd8 && buffer[2] == 0xff && (buffer[3] & 0xf0) == 0xe0)
        //if(buffer[0] == (unsigned char)0xff && buffer[1] == (unsigned char)0xd8 && buffer[2] == (unsigned char)0xff && (buffer[3] & (unsigned char)0xf0) == (unsigned char)0xe0)
        {
            //Update the filename. Make a new pointer with new filename.
            sprintf(filenamestring,"%03d.jpg", imagenumber);
            printf("this is filenamestring:\n%s\n",filenamestring);
            if(writingjpg)//imagenumber > 0
            {
             fclose(outptr);
             printf("closing file output pointer\n");
             outptr = fopen(filenamestring, "w"); //idk when to initialize
             imagenumber++;
            }
            else
            {
                writingjpg = true;
                //now is when we open new file open pointer
               outptr = fopen(filenamestring, "w"); //idk when to initialize
                fwrite(&buffer,512,1,outptr);//read from buffer,write to FILE*
            }


            if (outptr == NULL)
            {
                fclose(fileinputpointer);
                fprintf(stderr, "Could not create %s.\n", filenamestring);
                return 3;
            }

        }//end of "if header found"
    else//if header was not found
    {
        if(writingjpg)//imagenumber > 0
        {
            fwrite(&buffer,512,1,outptr);//read from buffer,write to FILE*

        }
    }
        //we write the things we just read to outpointer to the file--

        //because we hit EOF, it's time to close the file.
        if(bytesreturned != 1 )//1 chunk of 512 bytes
        {
             //we hit eof
             control = false;
        }
    }
}