I know this is a bit of cheating but if I use this code essentially I achieve what I want, albeit the thumbnails are loaded on the page unnecessarily.. <div style=”height:100px;overflow:hidden;”> </div>
Konstantin Kovshenin from Automattic built a small WP plugin hosted here at GitHUB, which does pretty much exactly what you are asking for. It does not seem to solve the whole migration as it works only for [nggallery] shortcodes, but anyone can fork it and add some more lines to solve the rest, right?
Search the posts by content for the string ‘[gallery’. You get an array of posts which you can list then in a widget or in plain PHP code.
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It seams like you forgot to set the Gallery Settings > Link thumbnails to: Image File! Go to edit page/post click on edit gallery inside of your editor and at the bottom you’ll find the Gallery Settings. Hope that helps.
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