Large document is sluggish and its pictures not visible in Web Layout

I too had this problem with a large document - Word 2013 was sluggish and not displaying pictures in web layout. The document was about 8 MB and 900 pages.

After some investigation I concluded this is a deficiency in Word's rendering of web layout.

For the record:

1. Various of ways of 'tidying up' the document had no effect (saving to rtf format and opening the rtf file; opening and saving in LibreOffice as docx and opening the docx file; repeating but using odt format; copying without the final pargraph mark; etc)
2. LibreOffice, although sluggish, was able to render the document in web layout
3. Using the old doc format allowed Word to render OK
4. Images display correctly near the start of the document
5. Splitting the document into subdocuments and a master shows the same problem

The clincher for me was discovering that the same picture inserted at successive locations rendered squashed up and then not at all. Here's a screenshot from the place in the document where things go wrong.

So there is a point in the document beyond which images do not render, as though a limit has been reached and an attempt is made to render the image by squashing it vertically. The limit varies with the pane size for displaying the document e.g. if the navigation pane is displayed the limit on image displaying is moved up the document.

This is a bug in Word's image rendering in Web Layout of the later file format.

In my case, since I wanted to use Word rather than switch to LibreOffice, and use docx rather than doc format, I split the document into several separate smaller documents; these display images OK although are a little inconvenient.

The long thread Word 2013: Extremely slow saving and pasting plain text in long documents, from January 2013, contains some workarounds that worked for some people.

Here is the list. I suggest to try them one-by-one and undo the ones that do not help:

1. Save As in "Word 97-2003 Document (*.doc)" format
2. Save the document in RTF file format, open a new Word 2013 document and import the RTF file, then save in Word 2013 format
3. Disable hardware acceleration in "Advanced settings"
4. Disable "Allow Background saves" (some people report that enabling Always create a backup on save also helps)
5. Turn off Background Repagination
6. Reduce the size of included pictures
7. Break apart the document and only rejoin the pieces when printing.
   See these references for master-subdocuments in Word :
   1. Understanding Master and Subdocuments
   2. Creating a Master Document Using Existing Subdocuments
8. Check add-ins in File / Options / Add-ins / Manage / COM Add-ins, and disable the ones you don't use. You can launch Winword with the parameter /safe to work without any add-in.
9. Change the default printer to a virtual PDF printer
10. Copy-paste the document to a new Word 2013 document
11. Disable "Spelling and Grammar Check"
12. Upgrade to Office 2016
13. Get a faster computer with more memory

The article 10 Microsoft Word 2013 headaches and how to cure them might also be useful.