Pictures: Problem after changing domain

Hi, few months ago I changed the domain of my blog, but kept the data on the same server than before. Since then I have a problem with the “picture pages” which you can link to a thumbnail in WP. On these picture pages the enlarged picture does not appear anymore; instead, there is a link to the picture itself. You can see an example here:

http://www.brennerbasisdemokratie.eu/?attachment_id=301

How come? And… how can I solve this?

By the way: Is there generally a possibility to modify an attachment page? For example, I’d like to change the text assigned to some pictures when I imported them…