Simple Read then Write .bmp File C code - c

Question

I am trying to do a simple read of a .bmp file, and then output that same .bmp file. Right now, it only works if the width and height are the exact same. That's a good indicator of what my problem is, but I can't seem to figure it out. I'm looking for any ideas or suggestions y'all may have. There are other questions about this, but they seem not to be exactly what I'm looking for. However, my output when the width and height are different is similar to the output that is shown here Read/Write SImple BMP Image C++ - basically it's skewed, incomplete, and repetitive, not the actual image.
Here is the code where I read in the .bmp file:
bool LoadBmp(const char *filepath)
{
FILE *f = fopen(filepath, "rb");
if (f)
{
Bwidth = 0;
Bheight = 0;
pixels = NULL;
unsigned char info[54] = {0};
fread(info, sizeof(unsigned char), 54, f);
Bwidth = *(unsigned int *)&info[18];
Bheight = *(unsigned int *)&info[22];
unsigned int size = Bwidth * Bheight * 3; // ((((Bwidth * Bheight) + 31) & ~31) / 8) * Bheight;
pixels = malloc(size);
fread(pixels, sizeof(unsigned char), size, f);
fclose(f);
return true;
}
return false;
}
Note that I was unsure whether to create size how I do below (Bwidth * Bheight * 3) or use what is commented out. Also note that 'Bwidth' and 'Bheight' are declared as unsigned int, whereas 'pixels' is defined as unsigned char*. Additionally, I purposely am not using a struct to store .bmp file data.
Here is the code that I use to write the .bmp file that I just loaded:
static bool WriteBMP(int x, int y, unsigned char *bmp, char * name)
{
const unsigned char bmphdr[54] = {66, 77, 255, 255, 255, 255, 0, 0, 0, 0, 54, 4, 0, 0, 40, 0, 0, 0, 255, 255, 255, 255, 255, 255, 255, 255, 1, 0, 8, 0, 0, 0, 0, 0, 255, 255, 255, 255, 196, 14, 0, 0, 196, 14, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
unsigned char hdr[1078];
int i, j, c, xcorr, diff;
FILE *f;
xcorr = (x+3) >> 2 << 2; // BMPs have to be a multiple of 4 pixels wide.
diff = xcorr - x;
for (i = 0; i < 54; i++) hdr[i] = bmphdr[i];
*((int*)(&hdr[18])) = xcorr;
*((int*)(&hdr[22])) = y;
*((int*)(&hdr[34])) = xcorr*y;
*((int*)(&hdr[2])) = xcorr*y + 1078;
for (i = 0; i < 256; i++) {
j = i*4 + 54;
hdr[j+0] = i; // blue
hdr[j+1] = i; // green
hdr[j+2] = i; // red
hdr[j+3] = 0; // dummy
}
f = fopen(name, "wb");
if (f) {
assert(f != NULL);
c = fwrite(hdr, 1, 1078, f);
assert(c == 1078);
if (diff == 0) {
c = fwrite(bmp, 1, x*y, f);
assert(c == x*y);
} else {
*((int*)(&hdr[0])) = 0; // need up to three zero bytes
for (j = 0; j < y; j++) {
c = fwrite(&bmp[j * x], 1, x, f);
assert(c == x);
c = fwrite(hdr, 1, diff, f);
assert(c == diff);
}
}
fclose(f);
return true;
}
else return false;
}
Thanks in advance for your help. I appreciate your time!