Photoshop doesn’t have a “project” file that contains multiple file references, but there are two possible approaches you could look into.
1) Bridge: Adobe’s file management system, you can store and organize files for any project in it.
2) Smart layers: Importing a (layered) Photoshop document into another Photoshop document gives you the option of making it a smart layer, essentially giving you a Photoshop document inside a Photoshop document. The smart layer will appear to be a single layer in the main document, but you can fully edit the inserted document by double-clicking it, it will open the layered “original”. There are other (better) reasons for using smart layers, particularly the fact that they can retain many live editable effects that regular layers can’t, for example as warp. Also, you can import Illustrator files as smart layers, retaining their editability. Smart layers are not specifically meant for project management, but can be used in the described manner. Obviously having many smart layers will increase the size of the file, since everything is stored there.
PS. Smart layers are very useful in other ways, so it is good to know about them. For instance, several copies of a smart layer in the same document are treated as one single source document, so if you edit one, the changes ripple throughout the other copies, retaining their effects. So you can, for instance, warp three copies of a smart layer to create faces of a cube and then edit one of the smart layers, replacing the source image and all three layers will be replaced upon saving. And that’s a very simple example.
Kalleheikki Kannisto
Senior Graphic Designer