To compress a picture:

1. Choose Compression Settings from 
    the Image menu and indicate the 
    settings you want.

    If you’re not sure what settings  
    to choose, use the default settings.
    For details about the settings, see
    “Changing Compression Settings.”
 
2. Click OK.

3. Make sure the picture you want
    is the active window. Click in the 
    window to make it active.