Converting TIF to PDF, wrong resolution

I have a TIF document, 1000px x 1000px (width x height) with vertical resolution 100dpi and horizontal resolution 200dpi, but after converting to PDF using Livecycle, the whole image squeezed vertically,  just like a 1000px x 500px image, but it has no such problem when I convert that TIF directly using Acrobat 8.0.

Any users also have this problem? Any solutions or workaround for this? Thanks!