Reading and writing binary file in C language

I tried to read and write fild in C but it failed. It partly worked, but the original file and the output file is not same. I tried to read and write bmp file.

FILE* openFile = fopen(argv[1], "rb");                      
FILE* writeFile = fopen(strcat(argv[1], ".cpd"), "wb");     
fseek(openFile, 0, SEEK_END);                               
long size = ftell(openFile);                                
char* bin = (char*)malloc(sizeof(char) * (size + 1));       
rewind(openFile);                                           
fwrite(bin, size, 1, writeFile);

//closefile, free, ...

Copyright Notice：Content Author:「Goldenbough」，Reproduced under the CC 4.0 BY-SA copyright license with a link to the original source and this disclaimer.
Link to original article：https://stackoverflow.com/questions/59208357/reading-and-writing-binary-file-in-c-language