Does the WebPack entry have to be a JavaScript File

When you use WebPack, you typically have to set an entry point to a .js file. Is this a requirement? I have two scenarios:

1. I want to convert a .scss to a .css file.
2. I want to minify images using imagemin.

I don't have or need any JavaScript. How can this be achieved using WebPack? Is that even the right tool? I've done this using Gulp in the past. Does WebPack only make sense when you require images and CSS from your JavaScript files?