diff --git a/src/applications/files/markup/PhabricatorImageRemarkupRule.php b/src/applications/files/markup/PhabricatorImageRemarkupRule.php
index c07ab9d496..5d1979ed3c 100644
--- a/src/applications/files/markup/PhabricatorImageRemarkupRule.php
+++ b/src/applications/files/markup/PhabricatorImageRemarkupRule.php
@@ -1,119 +1,171 @@
 <?php
 
 final class PhabricatorImageRemarkupRule extends PhutilRemarkupRule {
 
   const KEY_RULE_EXTERNAL_IMAGE = 'rule.external-image';
 
   public function getPriority() {
     return 200.0;
   }
 
   public function apply($text) {
     return preg_replace_callback(
       '@{(image|img) ((?:[^}\\\\]+|\\\\.)*)}@m',
       array($this, 'markupImage'),
       $text);
   }
 
   public function markupImage(array $matches) {
     if (!$this->isFlatText($matches[0])) {
       return $matches[0];
     }
 
     $args = array();
     $defaults = array(
       'uri' => null,
       'alt' => null,
       'width' => null,
       'height' => null,
     );
 
     $trimmed_match = trim($matches[2]);
     if ($this->isURI($trimmed_match)) {
       $args['uri'] = $trimmed_match;
     } else {
       $parser = new PhutilSimpleOptions();
       $keys = $parser->parse($trimmed_match);
 
       $uri_key = '';
       foreach (array('src', 'uri', 'url') as $key) {
         if (array_key_exists($key, $keys)) {
           $uri_key = $key;
         }
       }
       if ($uri_key) {
         $args['uri'] = $keys[$uri_key];
       }
       $args += $keys;
     }
 
     $args += $defaults;
 
     if (!strlen($args['uri'])) {
       return $matches[0];
     }
 
     // Make sure this is something that looks roughly like a real URI. We'll
     // validate it more carefully before proxying it, but if whatever the user
     // has typed isn't even close, just decline to activate the rule behavior.
     try {
       $uri = new PhutilURI($args['uri']);
 
       if (!strlen($uri->getProtocol())) {
         return $matches[0];
       }
 
       $args['uri'] = (string)$uri;
     } catch (Exception $ex) {
       return $matches[0];
     }
 
     $engine = $this->getEngine();
     $metadata_key = self::KEY_RULE_EXTERNAL_IMAGE;
     $metadata = $engine->getTextMetadata($metadata_key, array());
 
     $token = $engine->storeText('<img>');
 
     $metadata[] = array(
       'token' => $token,
       'args' => $args,
     );
 
     $engine->setTextMetadata($metadata_key, $metadata);
 
     return $token;
   }
 
   public function didMarkupText() {
     $engine = $this->getEngine();
     $metadata_key = self::KEY_RULE_EXTERNAL_IMAGE;
     $images = $engine->getTextMetadata($metadata_key, array());
     $engine->setTextMetadata($metadata_key, array());
 
     if (!$images) {
       return;
     }
 
+    // Look for images we've already successfully fetched that aren't about
+    // to get eaten by the GC. For any we find, we can just emit a normal
+    // "<img />" tag pointing directly to the file.
+
+    // For files which we don't hit in the cache, we emit a placeholder
+    // instead and use AJAX to actually perform the fetch.
+
+    $digests = array();
     foreach ($images as $image) {
-      $args = $image['args'];
+      $uri = $image['args']['uri'];
+      $digests[] = PhabricatorHash::digestForIndex($uri);
+    }
+
+    $caches = id(new PhabricatorFileExternalRequest())->loadAllWhere(
+      'uriIndex IN (%Ls) AND isSuccessful = 1 AND ttl > %d',
+      $digests,
+      PhabricatorTime::getNow() + phutil_units('1 hour in seconds'));
+
+    $file_phids = array();
+    foreach ($caches as $cache) {
+      $file_phids[$cache->getFilePHID()] = $cache->getURI();
+    }
 
-      $src_uri = id(new PhutilURI('/file/imageproxy/'))
-        ->setQueryParam('uri', $args['uri']);
+    $file_map = array();
+    if ($file_phids) {
+      $files = id(new PhabricatorFileQuery())
+        ->setViewer(PhabricatorUser::getOmnipotentUser())
+        ->withPHIDs(array_keys($file_phids))
+        ->execute();
+      foreach ($files as $file) {
+        $phid = $file->getPHID();
 
-      $img = id(new PHUIRemarkupImageView())
-        ->setURI($src_uri)
-        ->setAlt($args['alt'])
-        ->setWidth($args['width'])
-        ->setHeight($args['height']);
+        $file_remote_uri = $file_phids[$phid];
+        $file_view_uri = $file->getViewURI();
+
+        $file_map[$file_remote_uri] = $file_view_uri;
+      }
+    }
+
+    foreach ($images as $image) {
+      $args = $image['args'];
+      $uri = $args['uri'];
+
+      $direct_uri = idx($file_map, $uri);
+      if ($direct_uri) {
+        $img = phutil_tag(
+          'img',
+          array(
+            'src' => $direct_uri,
+            'alt' => $args['alt'],
+            'width' => $args['width'],
+            'height' => $args['height'],
+          ));
+      } else {
+        $src_uri = id(new PhutilURI('/file/imageproxy/'))
+          ->setQueryParam('uri', $uri);
+
+        $img = id(new PHUIRemarkupImageView())
+          ->setURI($src_uri)
+          ->setAlt($args['alt'])
+          ->setWidth($args['width'])
+          ->setHeight($args['height']);
+      }
 
       $engine->overwriteStoredText($image['token'], $img);
     }
   }
 
   private function isURI($uri_string) {
     // Very simple check to make sure it starts with either http or https.
     // If it does, we'll try to treat it like a valid URI
     return preg_match('~^https?\:\/\/.*\z~i', $uri_string);
   }
 
 }