Nextgen shortcode question

Just upgraded nextgen to 2.0+, broke about 50 posts with thumbnail galleries in them. Discovered that something like this…
<img class=”ngg_displayed_gallery mceItem” src=”http://mysite.com/nextgen-attach_to_post/preview/id–1788&#8243; alt=”” />
… replaces this…
[nggallery id=gallery_name]
That’s fine, but these new ids don’t correspond to the ones displayed in the manage galleries section of the plugin. Where would I find id–1788 if I wanted to rapidly fix all my posts?