magic bytes

Methodology

1. Use hexeditor to change the hex chars

2. Change magic bytes as per extension required.

Magic Bytes

# 16
PNG: 89 50 4e 47 0d 0a 1a 0a 00 00 00 0d 49 48 44 52

# 6
GIF:
GIF87a: 47 49 46 38 37 61
GIF89a: 47 49 46 38 39 61

# 4
JPEG: ff d8 ff e0