[Plugin: NextGEN Gallery] Output filters seem limited

Hi all
First off, I hope my topic title is OK, I just followed what seems to be the convention.

The reason I am here is I have a client that is using wordpress, with the brilliant NextGEN Gallery (shameless suck-up), and they have asked me for a small customization.

All they are looking for is an extra field to save with each image. There were plenty of places to hook into to add the extra fields for saving and displaying in the admin-panel.

But now I am trying to display the custom fields in the gallery, and I can’t find a filter that is useful. All the filters seem to take the already ‘compiled’ template as a sting (eg ngg_gallery_output).

Wouldn’t it be more useful to have a filter on the array of pictures that is passed to the template? That way you could call a custom template (seems to already be possible), and do what you want with all the data available?

Have I missed something in the plugin, or just in concept? I know I could add the query to get the custom fields into the template, but I want to avoid that as it seems bad practise.

Any suggestions?
Thanks in advance