Graphics, Frames, change default size.

OK.  I see what you want.  There are several ways do this, but try the following:

1. Create a new document from the File menu and set the size to 5x5 inches
2. Add the frame to the document
3. Stretch the frame by its handles to fill the document
4. Double-click on the place holder and navigate to the 5x5 image you want to fill it.

However, if all you want is a simple black frame around your photo, you can open the image and select the entire picture by clicking Ctrl+A.  Then go to Edit>Stroke (outline) Selection and add a frame size in pixels and the color of your frame.  Here, I placed a black frame around the white "image". 

What OS and version of Elements are you using?  Didn't the frame automatically wrap around your photo when you applied it?  If the frame layer contains a smart object, use the context menu to simplify the layer.  Select the frame layer, then Cmd/Ctrl+T to Free Transform the layer.  You should then be able to use the frame layer handles to fit it to the size of your image.  If this doesn't work, please give us a screenshot of what you are seeing and include the layers panel.

Edited:  There is no need to simplify the frame layer.