Is there any Mac software out there for scientific image management?
Metadata and smart folders are supported as part of OS X and integrated into Finder. Very basic example:


In Finder, pick any file(s) you want and select Get Info
In the Spotlight Comments field, enter tags, such as @fluid or @simulation (separate them by spaces).
From the File menu, select New Smart Folder
Click the plus icon to the right of Save
Select type Spotlight Comment (under Other...) and enter the tags you want in this smart folder, for example @fluid
Save and add the new smart folder to the Finder sidebar
Select the new smart folder and you will see all files with the @fluid tag


Preview.app can view all of the above file types you've mentioned (and Quicktime + Perian can do so for movies). Now you just need an image editor for the rest.