WebView uses the Internet Explorer engine to render the web pages (or Edge in UWP), to get started you can download the sample provided by Microsoft on GitHub: Windows-universal-samples/Samples/WebView at master · Microsoft/Windows-universal-samples · GitHub
]. You can also learn more about this control at MSDN, WebView class - Windows app development
Now to answer your question, what sort of images do you want to download? As I mentioned, the control is already powered by Internet Explorer (or Edge), and thus you do not need to perform any action and browser will itself provide the basic controls to the users. You mention,
Simply, just build the web browser application. If you need to get more control over it, consider reading a bit about Chakra engine that powers JS engine in Edge.
Quote:save image without downloading
Saving the image is performed by downloading the image, either to memory, or to hard drive. Browsers basically load the pages to memory, then to cache them they store them in hard drive if required. So basically, they end up downloading them.