So if you're e.g. using a file explorer (one app) to browse through your storage and then open an HTML file in a browser (a different app), then the browser is officially unable to resolve any relative paths in that HTML files, so no images, no links, no style sheets, no scripts, no nothing.
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[1] In Chrome, IE, an Edge definitely. Not sure about Firefox or Safari.
> Not sure about Firefox
It does that, too.