diff --git a/src/aphront/response/AphrontResponse.php b/src/aphront/response/AphrontResponse.php
--- a/src/aphront/response/AphrontResponse.php
+++ b/src/aphront/response/AphrontResponse.php
@@ -192,19 +192,21 @@
   public function getCacheHeaders() {
     $headers = array();
     if ($this->cacheable) {
+      $cache_control = array();
+      $cache_control[] = sprintf('max-age=%d', $this->cacheable);
+
       if ($this->canCDN) {
-        $headers[] = array(
-          'Cache-Control',
-          'public',
-        );
+        $cache_control[] = 'public';
       } else {
-        $headers[] = array(
-          'Cache-Control',
-          'private',
-        );
+        $cache_control[] = 'private';
       }
 
       $headers[] = array(
+        'Cache-Control',
+        implode(', ', $cache_control),
+      );
+
+      $headers[] = array(
         'Expires',
         $this->formatEpochTimestampForHTTPHeader(time() + $this->cacheable),
       );
diff --git a/src/applications/files/markup/PhabricatorEmbedFileRemarkupRule.php b/src/applications/files/markup/PhabricatorEmbedFileRemarkupRule.php
--- a/src/applications/files/markup/PhabricatorEmbedFileRemarkupRule.php
+++ b/src/applications/files/markup/PhabricatorEmbedFileRemarkupRule.php
@@ -16,6 +16,10 @@
     $objects = id(new PhabricatorFileQuery())
       ->setViewer($viewer)
       ->withIDs($ids)
+      ->needTransforms(
+        array(
+          PhabricatorFileThumbnailTransform::TRANSFORM_PREVIEW,
+        ))
       ->execute();
 
     $phids_key = self::KEY_EMBED_FILE_PHIDS;
@@ -109,7 +113,15 @@
         default:
           $preview_key = PhabricatorFileThumbnailTransform::TRANSFORM_PREVIEW;
           $xform = PhabricatorFileTransform::getTransformByKey($preview_key);
-          $attrs['src'] = $file->getURIForTransform($xform);
+
+          $existing_xform = $file->getTransform($preview_key);
+          if ($existing_xform) {
+            $xform_uri = $existing_xform->getCDNURI();
+          } else {
+            $xform_uri = $file->getURIForTransform($xform);
+          }
+
+          $attrs['src'] = $xform_uri;
 
           $dimensions = $xform->getTransformedDimensions($file);
           if ($dimensions) {
diff --git a/src/applications/files/query/PhabricatorFileQuery.php b/src/applications/files/query/PhabricatorFileQuery.php
--- a/src/applications/files/query/PhabricatorFileQuery.php
+++ b/src/applications/files/query/PhabricatorFileQuery.php
@@ -15,6 +15,7 @@
   private $maxLength;
   private $names;
   private $isPartial;
+  private $needTransforms;
 
   public function withIDs(array $ids) {
     $this->ids = $ids;
@@ -117,6 +118,11 @@
     return $this;
   }
 
+  public function needTransforms(array $transforms) {
+    $this->needTransforms = $transforms;
+    return $this;
+  }
+
   public function newResultObject() {
     return new PhabricatorFile();
   }
@@ -218,6 +224,44 @@
     return $files;
   }
 
+  protected function didFilterPage(array $files) {
+    $xform_keys = $this->needTransforms;
+    if ($xform_keys !== null) {
+      $xforms = id(new PhabricatorTransformedFile())->loadAllWhere(
+        'originalPHID IN (%Ls) AND transform IN (%Ls)',
+        mpull($files, 'getPHID'),
+        $xform_keys);
+
+      if ($xforms) {
+        $xfiles = id(new PhabricatorFile())->loadAllWhere(
+          'phid IN (%Ls)',
+          mpull($xforms, 'getTransformedPHID'));
+        $xfiles = mpull($xfiles, null, 'getPHID');
+      }
+
+      $xform_map = array();
+      foreach ($xforms as $xform) {
+        $xfile = idx($xfiles, $xform->getTransformedPHID());
+        if (!$xfile) {
+          continue;
+        }
+        $original_phid = $xform->getOriginalPHID();
+        $xform_key = $xform->getTransform();
+        $xform_map[$original_phid][$xform_key] = $xfile;
+      }
+
+      $default_xforms = array_fill_keys($xform_keys, null);
+
+      foreach ($files as $file) {
+        $file_xforms = idx($xform_map, $file->getPHID(), array());
+        $file_xforms += $default_xforms;
+        $file->attachTransforms($file_xforms);
+      }
+    }
+
+    return $files;
+  }
+
   protected function buildJoinClauseParts(AphrontDatabaseConnection $conn) {
     $joins = parent::buildJoinClauseParts($conn);
 
diff --git a/src/applications/files/storage/PhabricatorFile.php b/src/applications/files/storage/PhabricatorFile.php
--- a/src/applications/files/storage/PhabricatorFile.php
+++ b/src/applications/files/storage/PhabricatorFile.php
@@ -56,6 +56,7 @@
   private $objects = self::ATTACHABLE;
   private $objectPHIDs = self::ATTACHABLE;
   private $originalFile = self::ATTACHABLE;
+  private $transforms = self::ATTACHABLE;
 
   public static function initializeNewFile() {
     $app = id(new PhabricatorApplicationQuery())
@@ -1208,6 +1209,15 @@
       ->setURI($uri);
   }
 
+  public function attachTransforms(array $map) {
+    $this->transforms = $map;
+    return $this;
+  }
+
+  public function getTransform($key) {
+    return $this->assertAttachedKey($this->transforms, $key);
+  }
+
 
 /* -(  PhabricatorApplicationTransactionInterface  )------------------------- */