This page describes how to use tiff2mebes to convert many Tiff files to GDSII or MEBES in batch mode.
First, make sure all the TIFF files are stored in one directory and have a .tif extension.
Next, you should create in the same directory a batch file (for example, convert.bat) that has the following line in it.

for %%f in (*.tif) do c:\wcad\tiff2mebes\tiff2mebes.exe -gds -pixel:2 %%f