Here is the way to export an Erwin schema to a picture file, which I learned from my company’s DBA.

Edit/Copy, then choose picture. You can then choose Metafile or Bitmap (no GIF or JPG, but you should be able to get a bitmap to one of those formats if you wish). This will of course save it to the clipboard, you’ll need to paste it somewhere like a Word document or better yet an image editor.