I'm still not sure exactly what you're asking, because I don't understand what the project is, or what you're trying to achieve.
If you've created a database purely so that an artist can search and browse for relevant images, then the best bet is to set up the php page so that when the jpeg link is clicked, it downloads the appropriate eps file to the artists desktop. Then it can be placed into the document as per usual.
If you want the artist to work with images stored in a central location (ie your server hard drive), and not download the images, then you set up the php page to display the path with the name and location of the eps file, so that the artst can navigate directly to it from ID.
Either way, to avoid massive ID files you should avoid embedding images, which means that the eps images should be "placed" in ID from wherever they are stored.