Samsung and scanning to PDF in macOS Mojave
… is broken. There is no way to use default Image Capture application with Samsung SCX-4500W printer. However, there is hope :)
You can download
When you open this page, make sure to choose macOS 10.3 – there is no application for macOS Mojave.
Once application is installed, you can use it for scanning pages directly to PDF files – it will not crash the same way Image Capture does. Also, you will be able to open files inside Preview :)