Select the picture.
Click the Format tab under Picture Tools.
Click the Compress Pictures button.
Select the Apply to selected pictures only to apply compression setting to only the selected picture.
Or clear the check box to compress all pictures in your workbook.
Click Options.
Select or clear the Automatically perform basic compression on save.
Select or clear the Delete cropped areas of pictures to reduce file.
Click the Print, Screen, or E-mail option to select a target output.