Read-end-of-file possible ?

my task is to read out metadata of 3,000 tif files, 3 MB each. most of the needed data is in the script header, so i can use this code

            Local $open=FileOpen($file,16),$r=FileRead($open,700)
            FileClose($open)

which only reads out the first 700 bytes of the pics. my script manages this in 20 seconds for all 3,000 files.

now the problem is, i need also some bytes, maybe 100, from the end of the file. if i read the entire file out, it needs several hours (estimated). the autoit logic always reads a file from the start.

question is: does anyone know a method to only extract x bytes from the end of a file ?

thx for your help

E.

edit: maybe _WinAPI_ReadFile() can do that ? if so, can i have an example how to do it ?