I installed Calibre.

With no instruction from me and no notice, Calibre removed all the images from a document and replaced the image with the "Image" or Image No. xx.

Is that normal behavior?

What happens to my book if I delete Calibre. Does it remain as it is?

I need to use the document. Can anyone tell me how to restore my images?
If I understand what you wrote in two rather similar messages, you installed calibre. You did not open your Word document with calibre nor did you attempt to convert the Word document to a different format using calibre. This from from your "I did nothing" wordage.

You opened your critical Word document with Word and the images were gone. You also stated that the images were gone from all your other Word files. What format were the images? Which version of Word are you using? What OS is your computer running?

If you are running Windows, open a command prompt and try removing calibre's file type associations using:
They can be restored using:
This is likely to require opening a administrator command prompt.

As for calibre support, most calibre support is what you see freely offered in the calibre forum.
Thank you for your thoughtful information.
Here is more detail. The file was a Libre Office Write document. I installed Calibre.
I did not tell it to do anything.
Now, in every word-processing document, the image has been replaced by A tiny icon that looks like blue mountains, and in red, "Image8", for example. I tried to find a Calibre folder with the images. I could not. I opened a file with a name like my original file and it appeared with different page formatting, but by moving through it I could find and save the images. When I delete the image in my file or try to replace them the image does not appear, but only the Calibre file name, for example, "Image(a numeral)
I uninstalled Calibre. Nothing changed. I found on the web an original of the first image in the file and saved it in the same directory with the images I had recovered from Calibre. When the old image placeholder..."Image8" is deleted and the new one is pasted it does not pase the new copy of the image, but still shows the little thumbnailand "Image8", in red.
I have the Calibre install program. It appears that C. may have done something to my original file.
Can I install C. again and use it to fix this?
Calibre does not change the source in a From > To conversion
OTOH If you process (convert ) to the same type, it does.
Depending on your settings, you may have an original_xyz in the formats area of the MDE

Also Calibre remembers the settings used for each conversion (you can adjust them at the conversion start). Note the button at te bottom: That grab the latest Preferences (your default)
Thank you for your help.
I do not understand. I did not open Calibre. I installed it only. I did not knowingly or intentionally open a file or give any command.
The OS is Windows 10, up to date.
If you didn't even start calibre it wouldn't have done anything to any of your files. Unlike some music and video organisers calibre does NOT scan your system looking for data it can process….

At the end of the install did it pop up a screen that looked like this?

show attachment »

If so what did you do?

BR
I don't know if I related to a screen like that.
I uninstalled Calibre.
I uninstall my word processing software LibreOffice Write to remove any changes that Calibre has made, and reinstall it.

I create a new word processing file using Write.

I go to a web site and copy an image.

Paste the image into the word processor. In place of the image is a small thumbmnail that looks like blue mountains and the text "Image8", or a different number in red.

This means to me that Calibre has added some function to the word processor, or there is still some component of Caibre on my machine.
I opened command prompt, c:\Windows and pasted in the recommended command.
"calibre-debug --default-programs=unregister". The space before the two hyphens before "default" is as I received the command. Systemy returns that it is not a command.

Please help.
Is it intentional to put ads inside a post?
Calibre didn't modify any LibreOffice setting, nor did it modify any file that you didn't import into its library. It seems to me that this problem is unrelated to Calibre and only coincidently appeared at that moment. May I suggest that you ask for help on the LibreOffice support forum? (https://ask.libreoffice.org/)

Since you already uninstalled calibre, it is normal that this command does nothing.