Compress the pictures in a document
Follow these steps:
1. If you want to compress only some pictures, select them. Otherwise, click one picture so that Word makes the Picture Tools section of the Ribbon available.
2. On the Format tab, in the Adjust group, click Compress Pictures button:

3. If you want to compress only the picture or pictures you chose in step 1, select the Apply To Selected Pictures Only check box in the Compress Pictures dialog box. To compress all the pictures, leave this check box cleared:

4. Click the Options... button to open the Compression Settings dialog box:

5. Choose settings in the Compression Options area:
- Automatically Perform Basic Compression On Save - Select this check box if you want Word to use its normal compression whenever you save the document. This compression retains high quality but minimizes bloat.
- Delete Cropped Areas Of Pictures - Select this check box if you want Word to get rid of any parts you crop off pictures. If you clear this check box, Word merely hides the "cropped" parts. This hiding is good if you want to be able to restore the cropped parts, but it's bad for file size, and it may also have security implications (for example, a customer may be able to restore a part of a graphic that you had intended to crop off a document).
6. In the Target Output area, select the Print (220 ppi) option button, the Screen (150 ppi) option button, or the E-mail (96 ppi) option button to tell Word what picture quality you need (ppi is pixels per inch, and a higher number indicates higher quality). If you're not sure, use the Print setting - you can always reduce it later, but you can't restore information if you choose a lower setting.
7. Click the OK button. Word closes the Compression Settings dialog box and displays the Compress Pictures dialog box.
8. Click the OK button. Word compresses the pictures in the document.