I am turning *.doc files with photos into *.docx files. Typically the size reduces from 5MB to 500kB. I want to use Libre but where do I find the facility to do what Word 2010 can.
.odt files are always compressed. There is no need to explicitly request compression.
Be aware that .odt and .docx are two different formats based on different primitives. The conversion process does its best but is unable to apply global optimisation because Word has a less powerful design principle (weaker notion of styles). Therefore, the .odt version will be a bit bigger than what can be ultimately achieved if you review your files to fully style them.
To discover styles, read the Writer Guide.
To show the community your question has been answered, click the ✓ next to the correct answer, and “upvote” by clicking on the ^ arrow of any helpful answers. These are the mechanisms for communicating the quality of the Q&A on this site. Thanks!
In case you need clarification, edit your question (not an answer which is reserved for solutions) or comment the relevant answer.
In an Answer @Stan001 had written this comment: (Answer deleted).Thankyou for the advice. My problem is that I have 1000's of historical .doc files. All enormous in size. I am going thro them 1 by 1 reducing them by about 10x in size. I tried a VBS script in word that bulk turned .docs into .docxs but the script did not reduce the file size. Doing a "save as .docx" in Word does the reduction. I was hoping LO had an easy way of converting the very large .docs into very small .odts but the resulting .odts are about the same size.
.doc and perhaps .docx keep the editing history of the file, which causes the file size to grow. “Save as” resets the editing history. This explains why Word “Save as” results in file reduction.
Writer doesn’t keep editing history (unless “track changes” is enabled). “Save as” has then no impact on file size.
The main factor in @Stan001’s case is picture size. I created photo catalogues where I display thumbnails. Instead of using the original photo with scaling (this doesn’t change the file size), I created reduced thumbnails with GIMP (rescaling, resizing and resampling the original + JPEG compression) which resulted in a dramatic size reduction.
Probably, the strong reduction in size that can be achieved with Word is because Word can decrease the resolution of the embedded bitmaps upon saving. This is something Writer does not do: it internally maintains the original graphic in the file (allowing, of course, to eventually enlarge the file during later editing without having lost resolution of the source image.
@Vanadium: I think Writer has it right (if Word really reduces quality on its own). What user added in the document, the app must not modify in any way without user being notified and agreeing.
When you export to PDF, there is an option for specifying JPEG quality… It is then reduced on the fly, keeping the original unaltered in the document, so that you can apply a different processing next time.
See this topic: [Tutorial] Some useful hints on using images.
In fact, it depends on the way you have inserted your pics. Sometimes (especially when you drag and drop from another application), LO will take the pic as a png to avoid lossy compression. Thus, you may have inserted pictures in png that would have better been handled as jpg.
Better edit, crop, resize and save the pic first in a dedicated application (XnViewMP very good for that) and then insert with the toolbar button to add a picture.
You can check your pics by copying the .odt file and opening it with an archive manager. In the /pictures folder of that archive, you’ll find all your pics. Make sure their format is well suited.
The file size decrease from .doc to .docx may come from the fact that .doc is a binary format that is hardly compressed whereas .docx (like .odt) is compressed (it’s a mere zip container in fact).