3mb word file became 21mb file

[markcomp]

I opened a file for editing, it was about 3 mb. It contained graphics and tables. I edited it - changed 6 items of punctuation and 2 comments. When I saved it, it became 21 mb!!
At one point for no apparent reason, after I inserted a comment, the pointer changed from an arrow to a bar that had to be used above the letter. It disapeared later on its own.


Any ideas?