If you save your document as .docx, then you will be able to open it as zip-archive. There will be media folder with all images (mine had PNG images). You can then use programs like IrfanView, XnViewMP, FastStone Viewer to perform batch transformations like resize, reduce color depth, etc. Pack your images back into zip and rename it to docx.
For example, in my docx full of screenshots I needed to reduce number of colors to 8, which is enough for documentation purposes. After processing my 10MB doc became 1.8MB doc, so savings can be significant. Always save your original docx in case you want to restore pictures after too much degradation/processing etc.
For people who have issues with unzip/zip, here are the steps:
rename mydoc.docx mydoc.zip
mkdir mydoc_unzip
cd mydoc_unzip
unzip ../mydoc.zip
... manipulate ....
zip -a ../new_doc.zip *
cd ..
rename new_doc.zip new_doc.docx
I use a tool called Total Commander which allows me go directly inside docx file (Ctrl-PgDn), then I unpack(copy) media folder to temp location, do my manipulation, and copy media files back using Total Commander.
Once you rename docx to zip you should be able to explore it using Windows File Explorer - the steps will be as with Total Commander - copy media folder outside to temp location, manipulate images, copy them back into zip.
Thanks. Your first suggestion of using macro is not an option for me. Your second suggestion does not seem to work; hitting F4 does not seem to do anything. Your third option is also same as second as far as F4 key is concerned. Based on my exploration I see this link where it clearly says multi select doesnt work and points to KUTools only.
– Narayanan – 2015-07-16T04:52:51.047I checked the solutions 1,2,3. All of them works correctly. – M-Razavi – 2015-07-16T10:02:49.077
1My apologies; I overlooked the step of unlocking the aspect ratio as I do not want my images to go skewed. Rather I left locked, changed the width and set the aspect ration unlocked and F4 key worked. Bizarre! – Narayanan – 2015-07-16T10:34:04.937
OP asks about resizing. I think Razavi answers that correctly, here. But for others: if it's just a matter of image size (in memory)/resolution , maybe "Compress Pictures" would work . It seems "Compress Pictures" can work against ALL images in a doc, rather than one-at-a-time. I assumed it could only do one-at-a-time, which is why I came here.
– The Red Pea – 2017-01-04T21:15:18.6603
The 2nd solution is just great! Working with MS Office for ages but never came across that F4 key! Some additional information: https://techforluddites.com/f4-the-magic-ms-office-key-no-one-knows-about/
– Andreas – 2017-02-21T11:39:38.563Thanks a ton!! For MAC users use "command - Y" instead of F4 – user1707141 – 2019-03-11T05:46:25.737