Yes. There was also a image pack but it didn't illustrate every scene, far from it.
It's a text game, even with the image pack at most you had one image for 1 out 20 scenes.You have to read it and yes, use your imagination.
Don't pass on it too fast tho. There is a lot a fun in reading some of those scenes, especially if you try to create a character that you like (you have a lot of options)
Edit : I'm pretty sure you can find fan art for most of the characters, there is even a hentai comic about CoC1 Original.