Working with binary GIF files - Python Programming Exercise

def validate_gif(file_name):
    """
    Validates the structure of a GIF file by checking the first four bytes
    and identifying the GIF version (87 or 89).
    
    Parameters:
    file_name (str): The name of the GIF file to validate.
    """
    try:
        # Open the file in binary mode to read the first few bytes
        with open(file_name, 'rb') as file:
            # Read the first 6 bytes
            header = file.read(6)
            
            if len(header) < 6:
                print("Error: The file is too small to be a valid GIF image.")
                return
            
            # Check if the first four bytes are 'G', 'I', 'F', and '8'
            if header[:4] == b'GIF8':
                # Check the 5th byte to determine the GIF version
                version = header[4:5]
                
                if version == b'7':
                    print("The file is a valid GIF87a image.")
                elif version == b'9':
                    print("The file is a valid GIF89a image.")
                else:
                    print("Error: Invalid version detected in GIF file.")
            else:
                print("Error: The file is not a valid GIF image (incorrect header).")
    
    except FileNotFoundError:
        print(f"Error: The file '{file_name}' was not found.")
    except Exception as e:
        print(f"An error occurred: {e}")

# Main program execution
if __name__ == "__main__":
    file_name = input("Enter the name of the GIF file to validate (with extension, e.g., image.gif): ")
    validate_gif(file_name)

 Output

User Input:

Enter the name of the GIF file to validate (with extension, e.g., image.gif): example.gif
Program Output:

If the file is a valid GIF87a image:

The file is a valid GIF87a image.

If the file is a valid GIF89a image:

The file is a valid GIF89a image.
If the file has an incorrect header or version:

Error: The file is not a valid GIF image (incorrect header).
If the file is too small:

Error: The file is too small to be a valid GIF image.