around line 547 in tumblrize.php change
<optgroup label="Select">
<option value="regular"<?php if ('regular' === $tumblr_post_type) : print ' selected="selected"';endif;?>>Text</option>
<option value="photo"<?php if ('photo' === $tumblr_post_type) : print ' selected="selected"';endif;?>>Photo</option>
<option value="link"<?php if ('link' === $tumblr_post_type) : print ' selected="selected"';endif;?>>Link</option>
<option value="quote"<?php if ('quote' === $tumblr_post_type) : print ' selected="selected"';endif;?>>Quote</option>
<option value="audio"<?php if ('audio' === $tumblr_post_type) : print ' selected="selected"';endif;?>>Audio</option>
<option value="video"<?php if ('video' === $tumblr_post_type) : print ' selected="selected"';endif;?>>Video (YouTube)</option>
</optgroup>
to:
<optgroup label="Select">
<option value="photo"<?php if ('photo' === $tumblr_post_type) : print ' selected="selected"';endif;?>>Photo</option>
<option value="regular"<?php if ('regular' === $tumblr_post_type) : print ' selected="selected"';endif;?>>Text</option>
<option value="link"<?php if ('link' === $tumblr_post_type) : print ' selected="selected"';endif;?>>Link</option>
<option value="quote"<?php if ('quote' === $tumblr_post_type) : print ' selected="selected"';endif;?>>Quote</option>
<option value="audio"<?php if ('audio' === $tumblr_post_type) : print ' selected="selected"';endif;?>>Audio</option>
<option value="video"<?php if ('video' === $tumblr_post_type) : print ' selected="selected"';endif;?>>Video (YouTube)</option>
</optgroup>
and photo should be selected automatically now