Did you know that you can sometimes make your file size smaller by compressing the pictures in your Word document?
When you insert a picture into your Word document, Word saves it in its original full resolution state, even if you go and crop or resize it. By keeping this information, you can undo your cropping or make the picture larger and Word will have all of the information it needs to do so. If you're sure that one or more pictures in your document are sized and cropped properly, however, you can go ahead and compress them to reduce your file size. This won't affect the quality of your picture(s).
Select the picture you'd like to compress by clicking on it. Go to 'Picture Tools' on your ribbon, then select 'CompressPictures' (it's in the 'Adjust' group on the 'Format' tab). If you want to compress every picture in your document and not just the one you've selected, make sure you uncheck the 'Apply to selected pictures only' check box.
I find this to be a really big help in saving space on my hard drive when I'm working with image-heavy documents. Sometimes you don't notice how big the file is until you go to e-mail it to someone and it takes forever because it's so large. Happy compressing, dear readers!