Da musst du dir die Specification deiner einzelnen Formate ansehen. Meist sind in den ersten Bytes jeder Datei noch irgendwleche Kennungen hinterlegt. In deinem genannten Fall liegt die Spec bei Adobe. [
url=http://partners.adobe.com/public/developer/tiff/index.html]
Zitat:
A TIFF file begins with an 8-byte image file header, containing the following
information:
Bytes 0-1:
The byte order used within the file. Legal values are:
“II” (4949.H)
“MM” (4D4D.H)
In the “II” format, byte order is always from the least significant byte to the most
significant byte, for both 16-bit and 32-bit integers This is called little-endian byte
order. In the “MM” format, byte order is always from most significant to least
significant, for both 16-bit and 32-bit integers. This is called big-endian byte
order.
Bytes 2-3
An arbitrary but carefully chosen number (42) that further identifies the file as a
TIFF file.
The byte order depends on the value of Bytes 0-1.
Bytes 4-7
The offset (in bytes) of the first IFD. The directory may be at any location in the
file after the header but must begin on a word boundary. In particular, an Image
File Directory may follow the image data it describes. Readers must follow the
pointers wherever they may lead.
The term byte offset is always used in this document to refer to a location with
respect to the beginning of the TIFF file. The first byte of the file has an offset of
0.
Also du musst eine 42 an Byte 2-3 finden und vorher in Byte 0 und 1 schauen, ob es Big oder Little Endian ist.