Numbers 
Replace template placeholders
Most Numbers templates include placeholder charts, tables, text, and images that you can edit, replace, or delete.
Replace placeholder text
Select the text, then enter your own.
Replace a placeholder image
-
Click
on the placeholder image to see your photos from iPhoto or Aperture, then click the photo you want.
You can also drag an image from the Finder onto the placeholder image.
To change the part of the image that’s visible, resize the mask for the image.
To remove a placeholder entirely, select it, then press Delete.