EPS

• An EPS file retains the properties of a vector image, which allows it to be editable by other programs. EPS files also have infinite resolution, which means that they can be scaled to any size without losing quality. However, some programs will not export EPS files with full functionality. Adobe Photoshop for instance may not export an EPS file in such a way that it can be edited because it is a bitmap editing program, not a vector graphics editor. If this is the case, try to break up the original image into different documents that indicate each layer, then import the documents into Illustrator one at a time.
  
  

Importing EPS Files

• To import an EPS file, you simply need to select "File" from the top menu, then "Import." Navigate to your EPS file and click "OK." If the EPS file was created in another program, Illustrator automatically will convert the vector objects to an Illustrator object. This usually shouldn't matter, but it can change some of the characteristics of your file. Colors, for instance, may change. If this is the case, you will want to link your EPS file, not import it.
  
  

How to Link EPS File

• Link to an EPS file by selecting "Window," then "Links Panel." Add a new document to the panel by clicking on the "Link" button at the bottom right of the panel. Embed this linked file into your document by highlighting the document and selecting "Embed Image" from the panel. This will be a small icon with various shapes in it at the bottom of the panel. This will insert your linked file into your document.
  
  

Using Linked Files

• The advantage of linking, instead of importing, an EPS file is that its characteristics will stay intact no matter what objects it uses, so it will look exactly the same. The disadvantage is that it is harder to edit the file. You will be able to increase the size of the image, as well as transform it, such as rotate it, but if you want to add colors or new shapes to it, you will have to use Layer masks. However, if you cannot edit your EPS file in any other way, this will be your best option.