If the images are screen grabs of documents, JPG is not the optimal format to use. JPG adds fuzzy edges to areas of black on white like text (especially around diagonal lines). I would recommend PNG files for that type of graphic and the file sizes will be much smaller. You will require a bit more resolution on line art graphics like that though (I normally choose 400dpi for that). If you only have JPGs then it is too late but if you could recapture the lineart images as PNGs then I think you can make some significant size savings and increase quality.

Don't use Word to downsample the graphics. Any downsampling should be done using proper bitmap editors like Adobe Photoshop, Paint.Net or similar.

__________________
Andrew Lockton
Chrysalis Design, Melbourne Australia