ios swift wkwebview

Loading local images into WKWebView

I’m trying to get WKWebView to display locally downloaded images in a WKWebView. The webview normally displays HTML, which is retrieved remotely. The contents of the HTML can sometimes contain remote links to images. My app parses the HTML and looks for these HTML tags, downloads the file it is referencing and subsequently replaces the remote link with a local one.

Normally speaking, this wouldn’t be very difficult but the images aren’t being displayed, presumably due to the images and the local HTML files for the webview being in two separate directories (the documents directory and the app bundle directory respectively).
I’ve seen people suggest moving the download destination of the images to the same directory as where the HTML files are but this isn’t an option for me as I don’t want to start mixing up files downloaded by the user with local assets.

What would be my best course of action here?