Here's something a little easier on the users, although certainly not
idiot-proof. ("Nothing is idiot-proof because idiots are so ingenious!")
Insert an ASK field in the document (preferably as a template) -- anywhere
in the body text is ok. In the Insert > Field dialog, select ASK, enter a
name for it, enter the prompt you want, and enter the letter Y as the
default value (and check the box next to "Default"). You'll get an invisible
field in the document, but you can see the field code if you press Alt+F9.
It might look like this:
{ASK PrintPicture "Print the picture?" \d Y}
What this does is create a bookmark named PrintPicture (or whatever you call
it) inside the invisible field. Whenever the field is updated, it will show
a box with the question, and an edit area for the user to enter a response.
The default response will be Y. Whatever is in the edit area when the user
clicks the OK button will become the value of the bookmark.
Next you need a field that displays the picture when the value of the ASK
bookmark is Y, and displays nothing when the value is anything except Y. To
make this, type the following line at the position where you want the
picture to appear (if you used a different name for the ASK field, use that
name here):
IF PrintPicture = Y
Type a space after the Y and then use Insert > Picture > From File to put
your picture in-line at the end of the line. Next, select just the word
PrintPicture and press Ctrl+F9. That makes it into a field whose value is
the value of the PrintPicture bookmark. Finally, select the whole line
including the picture, and press Ctrl+F9 again. Then press F9 to update the
field.
There's one more piece to this, and it's one you can't control directly.
Each user has to have the "Update fields" box checked in the Tools > Options
Print dialog. Some users may already have it checked, and others won't;
you'll have to ask them to make sure it's checked.
Now, when someone prints the document, the ASK box will pop up with the Y
already in place. If they just click OK, the document will print with the
picture. If they change the edit area at all (delete the Y, type a space,
type N, type "yes, please", etc.) the document will print without the
picture.
There are some other non-idiot-proof aspects to this: (a) If you select the
entire paragraph containing the ASK field and delete it, the ASK field will
also be deleted and the picture will never appear. (b) If the cursor is in
the ASK field's text area and you press Enter, it makes a new line in the
text area. To answer the question, you have to use the mouse to click OK, or
tab to the OK button and press Enter. (c) If the field containing the
picture is in the header/footer, it doesn't automatically update when you
print.