Many folks insert pictures into their Word documents. If you are one of those people inserting JPG images, you should consider using the Picture option on the Insert tab of your Ribbon, rather than copying and pasting and I will tell you why.
Word handles pictures differently when they are cut and pasted than when they are inserted. When you cut and paste an image into your Word document, Word treats it as TIFF file, which is much larger typically than JPG files, even if the image you started with was a JPG!
When you insert images into your document correctly, using the Picture tool, you can save tons of disc space and communication bandwidth if you have to e-mail your document. An added bonus is that your file will now load faster and you can more quickly make edits!