pset4 recover, cannot open jpg

Question

Can somebody please help me with the code, I couldnt figure out why the pictures cannot open. It's didn't show any error. Thanks.

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

int main(void)
{

    FILE *memorycard = fopen("card.raw","r"); 
    if( memorycard == NULL)
    {
        fprintf( stderr, "Cound not open forensic memorycard.");
        return 2;
    }

    //
    unsigned char readblock[512];  

    FILE* picture;
    picture = NULL; 

    char filename[8];

    int filecount;
    filecount = 0;

    int jpgfound;
    jpgfound = 0;



    while ( fread( readblock, 512, 1, memorycard) != 0)
    {
        //JPEG found
        if( readblock [0] == 0xff && readblock[1] == 0xd8 && readblock[2] == 0xff && (readblock[3] & 0xf0) == 0xe0)
        {


            if (jpgfound > 0 )
            {
                fclose(picture);
            }

            sprintf( filename, "%03i.jpg", filecount); 
            picture = fopen("filename", "w"); 

            if( picture == NULL)
            {
                fprintf(stderr, "Can't open file.\n");
            }

            printf( "%s", filename);


            filecount++;

            fwrite( &readblock, 512, 1, picture); //&
            jpgfound = 1;

        }

    }

        fclose(memorycard);

        return 0;
 }

Answer 1

"filename" is a string constant, a pointer to a string of {'f','i','l','e','n','a','m','e','\0'}.

filename instead is a variable of type char[8].

Pick the right one.