RECOVER Pset_4 CS50 - Images recovered are incomplete - cs50

Question

So I'm doing the CS50 pset4 recover task (where you need to search for jpg files on a memory card and whenever you find one- you open a new file and write the jpg found to the new file). I have written the code in a slightly different manner then what is told in the course but I think(hope) my logic is right. I am able to recover all 50 images but the images are incomplete and distorted. Also for some reason the 050th image is not opening. Here is my code
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
typedef uint8_t BYTE; //defining a byte = 8 bits or 8 0's or 1's
int main(int argc, char *argv[]) {
//assigning variables
int BLOCK_SIZE = 512;
BYTE buffer[BLOCK_SIZE];
int i = 0;
char* nf = malloc(sizeof(int)*3);
//checking to see a file name is given
if (argc != 2)
{
printf("Usage: ./recover IMAGE\n");
return 1;
}
//opening said file
FILE *rfile = fopen(argv[1], "r");
if(rfile == NULL)
{
printf("File '%s' does not exist\n", argv[1]);
return 1;
}
//opening a copy
FILE *c = fopen(argv[1], "r");
if(c == NULL)
{
printf("File '%s' does not exist\n", argv[1]);
return 1;
}
//checking 512 bytes again and again for orginal
while (fread (buffer, 1, BLOCK_SIZE, rfile) == BLOCK_SIZE)
{
fseek(c, ftell(rfile) , SEEK_SET); //fread (buffer, 1, BLOCK_SIZE, c);
sprintf(nf, "%03i.jpg", i); //000, 001, 002
//opening a file to write in
FILE *img = fopen(nf, "w");
if(img == NULL)
{
return 1;
}
//Is it a jpeg!?
if (buffer[0]==0xff && buffer[1]==0xd8 && buffer[2]==0xff && (buffer[3] & 0xf0) == 0xe0)
{
//writing the img in a file called img
fwrite(buffer, 512, 1, img);
fwrite(c, BLOCK_SIZE, 2048, img);
i++; //making sure a new file is opened next time
}
fclose(img);
}
fclose(c);
fclose(rfile);
free(nf); }