Convert tif to png from the command line

First download and install imagemagick for your OS of choice http://www.imagemagick.org/script/binary-releases.php, be sure to check out docs: http://www.imagemagick.org/script/command-line-processing.php
Then install ICC Profiles if you see problems related to colors:
http://www.adobe.com/support/downloads/detail.jsp?ftpID=4075

convert logo.tif  -profile "C:\Adobe ICC Profiles (end-user)\RGB\AdobeRGB1998.icc" -resize 300x309 logo.png

You might want to compress, here is a great tool just for that http://compresspng.com/