I am trying to set up a album of all images in other albums, is there any way to add a tag to an image by default. So I can have a 'dynamic album' of all images searched on one 'tag'. (bascially a photostream from all albums).
Also if this could be hidden album unless logged-in.

1. If you mean an easy way without coding, no. Otherwise use the object model or attach the tag via EXIF before uploading the image.

2. You can create dymanic albums via the object model, so coding required.

Thank you.