Reproducing an Image using C - c

Question

I'm trying to write a program to blur an image, but first of am trying to see if I can even reproduce the image, pixel by pixel, in another file. I've allocated a 2-dimensional char array to hold the value of each pixel in the image.
Note: The image is in grayscale, and it is of type .raw
However, whenever I attempt to read the pixels into my 2D array, my program crashes. I feel like it has something to do with me not looping through the dimensions of the image correctly, but I'm not sure.
Code:
#include <stdio.h>
#include <stdlib.h>
int main()
{
FILE *fin, *fout;
char path_in[64], path_out[64], **rev, px;
int width, height, read, i, j;
printf("Input file name: ");
scanf("%s", path_in);
printf("Output file name: ");
scanf("%s", path_out);
printf("Width of image (in pixels): ");
scanf("%d", &width);
printf("Height of image (in pixels): ");
scanf("%d", &height);
fin = fopen(path_in, "rb");
fout = fopen(path_out, "wb");
row = 0;
rev = (char **)malloc(height * sizeof(char));
for(i = 0; i < width; i++)
rev[i] = (char *)malloc(width * sizeof(char));
for(i = 0; i < height; i++)
{
for(j = 0; j < width; j++)
{
read = fread(&px, sizeof(char), 1, fin);
rev[i][j] = px;
}
}
fclose(fout);
fclose(fin);
return 0;
}
My program is pretty narrow, as it only accepts grayscale .raw image type.

Answer 1

Change these lines as this:
row = 0;
rev = malloc(height * sizeof *rev);
for(i = 0; i < width; i++)
rev[i] = malloc(width * sizeof **rev);
You were allocating memory for height chars, not for height pointers to chars, as you intended.
Also, don't cast the result of malloc if developing with C

Answer 2

This line: rev = (char **)malloc(height * sizeof(char));
should be rev = (char **)malloc(height * sizeof(char*));

Answer 3

I think is better to use contiguous memory to manage the image!
Using char ** in the way as in your code you don't have a block of memory that contains the whole image, but a lot of not contiguous vectors each one containing a line!
The following code reads the image in a contiguous block of memory using only one malloc:
char * rev;
/* HERE your code to insert width and height */
rev = malloc(height * width *sizeof(char));
if (rev==NULL) {
/* Ops! The buffer is not allocated!!! */
}
/* HERE you open the file and so on */
for(i = 0; i < height; i++)
{
for(j = 0; j < width; j++)
{
read = fread(&rev[i*width+j], sizeof(char), 1, fin);
if (read!=1) { /* 1 is the number of bytes fread reads if ok */
/* Ops, there's a problem! The fread didn't read! */
}
}
}
Using char * you might load all the image with one fread, thus avoiding the two for loops :)
fread(rev,witdh,height,fin);
In this way you may point each single pixel using:
rev[y*width+x];