diff --git a/_test/DokuAssetFetcherTest.php b/_test/DokuAssetFetcherTest.php
new file mode 100644
index 0000000..e6b5436
--- /dev/null
+++ b/_test/DokuAssetFetcherTest.php
@@ -0,0 +1,107 @@
+<?php
+
+namespace dokuwiki\plugin\dw2pdf\test;
+
+use dokuwiki\plugin\dw2pdf\src\Config;
+use dokuwiki\plugin\dw2pdf\src\DokuMpdf;
+use DokuWikiTest;
+use Mpdf\AssetFetcherInterface;
+use Mpdf\Mpdf;
+use ReflectionProperty;
+
+/**
+ * Tests for handing resolved media files over to mpdf.
+ *
+ * @group plugin_dw2pdf
+ * @group plugins
+ */
+class DokuAssetFetcherTest extends DokuWikiTest
+{
+    /**
+     * Get the asset fetcher of a fresh DokuMpdf instance with the given basepath setting.
+     *
+     * Depending on basepathIsLocal mpdf uses either the first or the second argument of
+     * fetchDataFromPath(), so both cases need to be tested. The flag is false on any install
+     * where the baseurl host differs from the request host, a non-default port being enough.
+     *
+     * @param bool $basepathIsLocal Value to force for the mpdf flag
+     * @return AssetFetcherInterface
+     */
+    protected function getFetcher(bool $basepathIsLocal): AssetFetcherInterface
+    {
+        $mpdf = new DokuMpdf(new Config(), 'en');
+        $mpdf->basepathIsLocal = $basepathIsLocal;
+
+        return (new ReflectionProperty(Mpdf::class, 'assetFetcher'))->getValue($mpdf);
+    }
+
+    /**
+     * @return array<string, array{0:string,1:string,2:bool}>
+     */
+    public static function fetchProvider(): array
+    {
+        global $conf;
+
+        $media = DOKU_URL . 'lib/exe/fetch.php?media=wiki:dokuwiki-128.png';
+        $mediaFile = $conf['mediadir'] . '/wiki/dokuwiki-128.png';
+        $static = DOKU_URL . 'lib/images/throbber.gif';
+        $staticFile = DOKU_INC . 'lib/images/throbber.gif';
+
+        return [
+            'fetch url, local basepath' => [$media, $mediaFile, true],
+            'fetch url, remote basepath' => [$media, $mediaFile, false],
+            'static file, local basepath' => [$static, $staticFile, true],
+            'static file, remote basepath' => [$static, $staticFile, false],
+        ];
+    }
+
+    /**
+     * The local file has to be read regardless of the basepath setting.
+     *
+     * The second argument is the unmodified source as mpdf passes it for every image.
+     *
+     * @dataProvider fetchProvider
+     */
+    public function testFetchDataFromPathReadsLocalFile(string $source, string $expected, bool $basepathIsLocal): void
+    {
+        $data = $this->getFetcher($basepathIsLocal)->fetchDataFromPath($source, $source);
+
+        $this->assertSame(file_get_contents($expected), $data);
+    }
+
+    /**
+     * The resolved file has to win over the source mpdf was originally given.
+     *
+     * With a local basepath mpdf prefers the second argument whenever it can open it. For a
+     * media URL that means an anonymous HTTP request back into the wiki instead of our local
+     * copy. A readable file stands in for such a loadable source here.
+     */
+    public function testFetchDataFromPathIgnoresOriginalSource(): void
+    {
+        global $conf;
+        $file = $conf['mediadir'] . '/wiki/dokuwiki-128.png';
+        $source = DOKU_URL . 'lib/exe/fetch.php?media=wiki:dokuwiki-128.png';
+        $loadable = DOKU_INC . 'lib/images/throbber.gif';
+
+        $data = $this->getFetcher(true)->fetchDataFromPath($source, $loadable);
+
+        $this->assertSame(file_get_contents($file), $data);
+    }
+
+    /**
+     * Our pseudo scheme has no stream wrapper, so it can only ever be read locally.
+     *
+     * @testWith [true]
+     *           [false]
+     */
+    public function testFetchDataFromPathReadsDw2pdfScheme(bool $basepathIsLocal): void
+    {
+        global $conf;
+        $file = $conf['mediadir'] . '/wiki/dokuwiki-128.png';
+        $source = 'dw2pdf://' . $file;
+
+        $data = $this->getFetcher($basepathIsLocal)->fetchDataFromPath($source, $source);
+
+        $this->assertSame(file_get_contents($file), $data);
+    }
+}
diff --git a/src/DokuAssetFetcher.php b/src/DokuAssetFetcher.php
index 82d2688..3668ae0 100644
--- a/src/DokuAssetFetcher.php
+++ b/src/DokuAssetFetcher.php
@@ -9,10 +9,21 @@
  */
 class DokuAssetFetcher extends AssetFetcher
 {
+    /**
+     * Load the given asset, preferring a local copy of Dokuwiki media over an HTTP request
+     *
+     * Both arguments are overwritten with the resolved file, because mpdf picks either one
+     * depending on its basepathIsLocal flag. Leaving a URL in one of them would make mpdf
+     * fetch the asset over HTTP again.
+     *
+     * @param string $path Media reference or URL to load
+     * @param string|null $originalSrc The unmodified source as given in the HTML
+     * @return string The asset's binary data, empty when it could not be loaded
+     */
     public function fetchDataFromPath($path, $originalSrc = null)
     {
         $resolved = (new MediaLinkResolver())->resolve($path);
-        if ($resolved) $originalSrc = $resolved['path'];
+        if ($resolved) $path = $originalSrc = $resolved['path'];
         return parent::fetchDataFromPath($path, $originalSrc);
     }
 }