Find hidden files in images

Checks a JPEG or PNG for two common ways people hide a file inside an image: data simply appended after the image's proper end marker, and a straightforward least-significant-bit encoding across the pixel data.

This is a best-effort check, not a forensic tool. Encrypted, compressed, or more sophisticated steganography (randomised bit placement, multi-file splitting, and so on) won't be detected — only the common, simple techniques above.