diff --git a/src/applications/files/controller/transform/PhabricatorFileTransformController.php b/src/applications/files/controller/transform/PhabricatorFileTransformController.php
index c766bbbaca..7f3a42253d 100644
--- a/src/applications/files/controller/transform/PhabricatorFileTransformController.php
+++ b/src/applications/files/controller/transform/PhabricatorFileTransformController.php
@@ -43,12 +43,10 @@ class PhabricatorFileTransformController extends PhabricatorFileController {
       return new Aphront404Response();
     }
 
-    if (!$file->isViewableInBrowser()) {
-      return new Aphront400Response();
-    }
+    $type = $file->getMimeType();
 
-    if (!$file->isTransformableImage()) {
-      return new Aphront400Response();
+    if (!$file->isViewableInBrowser() || !$file->isTransformableImage()) {
+      return $this->buildDefaultTransformation($file);
     }
 
     switch ($this->transform) {
@@ -78,6 +76,39 @@ class PhabricatorFileTransformController extends PhabricatorFileController {
     return $this->buildTransformedFileResponse($xform);
   }
 
+  private function buildDefaultTransformation(PhabricatorFile $file) {
+    static $regexps = array(
+      '@application/zip@'     => 'zip',
+      '@image/@'              => 'image',
+      '@application/pdf@'     => 'pdf',
+      '@.*@'                  => 'default',
+    );
+
+    $type = $file->getMimeType();
+    $prefix = 'default';
+    foreach ($regexps as $regexp => $implied_prefix) {
+      if (preg_match($regexp, $type)) {
+        $prefix = $implied_prefix;
+        break;
+      }
+    }
+
+    switch ($this->transform) {
+      case 'thumb-160x120':
+        $suffix = '160x120';
+        break;
+      case 'thumb-60x45':
+        $suffix = '60x45';
+        break;
+      default:
+        throw new Exception("Unsupported transformation type!");
+    }
+
+    $path = "/rsrc/image/icon/fatcow/thumbnails/{$prefix}{$suffix}.png";
+    return id(new AphrontRedirectResponse())
+      ->setURI($path);
+  }
+
   private function buildTransformedFileResponse(
     PhabricatorTransformedFile $xform) {
 
@@ -123,9 +154,25 @@ class PhabricatorFileTransformController extends PhabricatorFileController {
       $dx, $dy,
       $scale * $dx, $scale * $dy);
 
-    ob_start();
-    imagejpeg($dst);
-    return ob_get_clean();
+    $img = null;
+
+    if (function_exists('imagejpeg')) {
+      ob_start();
+      imagejpeg($dst);
+      $img = ob_get_clean();
+    } else if (function_exists('imagepng')) {
+      ob_start();
+      imagepng($dst);
+      $img = ob_get_clean();
+    } else if (function_exists('imagegif')) {
+      ob_start();
+      imagegif($dst);
+      $img = ob_get_clean();
+    } else {
+      throw new Exception("No image generation functions exist!");
+    }
+
+    return $img;
   }
 
 }
diff --git a/src/applications/files/storage/file/PhabricatorFile.php b/src/applications/files/storage/file/PhabricatorFile.php
index b2a53948cd..0c70be9320 100644
--- a/src/applications/files/storage/file/PhabricatorFile.php
+++ b/src/applications/files/storage/file/PhabricatorFile.php
@@ -216,7 +216,35 @@ class PhabricatorFile extends PhabricatorFileDAO {
   }
 
   public function isTransformableImage() {
-    return preg_match('@^image/(gif|png|jpe?g)@', $this->getViewableMimeType());
+
+    // NOTE: The way the 'gd' extension works in PHP is that you can install it
+    // with support for only some file types, so it might be able to handle
+    // PNG but not JPEG. Try to generate thumbnails for whatever we can. Setup
+    // warns you if you don't have complete support.
+
+    $matches = null;
+    $ok = preg_match(
+      '@^image/(gif|png|jpe?g)@',
+      $this->getViewableMimeType(),
+      $matches);
+    if (!$ok) {
+      return false;
+    }
+
+    switch ($matches[1]) {
+      case 'jpg';
+      case 'jpeg':
+        return function_exists('imagejpeg');
+        break;
+      case 'png':
+        return function_exists('imagepng');
+        break;
+      case 'gif':
+        return function_exists('imagegif');
+        break;
+      default:
+        throw new Exception('Unknown type matched as image MIME type.');
+    }
   }
 
   public function getViewableMimeType() {
diff --git a/src/infrastructure/setup/PhabricatorSetup.php b/src/infrastructure/setup/PhabricatorSetup.php
index 023de19800..ff4e559b79 100644
--- a/src/infrastructure/setup/PhabricatorSetup.php
+++ b/src/infrastructure/setup/PhabricatorSetup.php
@@ -165,6 +165,39 @@ class PhabricatorSetup {
 
     self::write("[OKAY] Basic configuration OKAY\n");
 
+
+    $issue_gd_warning = false;
+    self::writeHeader('GD LIBRARY');
+    if (extension_loaded('gd')) {
+      self::write(" okay  Extension 'gd' is loaded.\n");
+      $image_type_map = array(
+        'imagepng'  => 'PNG',
+        'imagegif'  => 'GIF',
+        'imagejpeg' => 'JPEG',
+      );
+      foreach ($image_type_map as $function => $image_type) {
+        if (function_exists($function)) {
+          self::write(" okay  Support for '{$image_type}' is available.\n");
+        } else {
+          self::write(" warn  Support for '{$image_type}' is not available!\n");
+          $issue_gd_warning = true;
+        }
+      }
+    } else {
+      self::write(" warn  Extension 'gd' is not loaded.\n");
+      $issue_gd_warning = true;
+    }
+
+    if ($issue_gd_warning) {
+      self::write(
+        "[WARN] The 'gd' library is missing or lacks full support. ".
+        "Phabricator will not be able to generate image thumbnails without ".
+        "gd.\n");
+    } else {
+      self::write("[OKAY] 'gd' loaded and has full image type support.\n");
+    }
+
+
     self::writeHeader('FACEBOOK INTEGRATION');
     $fb_auth = PhabricatorEnv::getEnvConfig('facebook.auth-enabled');
     if (!$fb_auth) {
diff --git a/webroot/rsrc/image/icon/fatcow/thumbnails/default160x120.png b/webroot/rsrc/image/icon/fatcow/thumbnails/default160x120.png
new file mode 100644
index 0000000000..16d6fd4f90
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diff --git a/webroot/rsrc/image/icon/fatcow/thumbnails/default60x45.png b/webroot/rsrc/image/icon/fatcow/thumbnails/default60x45.png
new file mode 100644
index 0000000000..145ea1eb63
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diff --git a/webroot/rsrc/image/icon/fatcow/thumbnails/image160x120.png b/webroot/rsrc/image/icon/fatcow/thumbnails/image160x120.png
new file mode 100644
index 0000000000..90cc11c02d
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diff --git a/webroot/rsrc/image/icon/fatcow/thumbnails/image60x45.png b/webroot/rsrc/image/icon/fatcow/thumbnails/image60x45.png
new file mode 100644
index 0000000000..9077e69586
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diff --git a/webroot/rsrc/image/icon/fatcow/thumbnails/pdf160x120.png b/webroot/rsrc/image/icon/fatcow/thumbnails/pdf160x120.png
new file mode 100644
index 0000000000..20f08f955b
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diff --git a/webroot/rsrc/image/icon/fatcow/thumbnails/pdf60x45.png b/webroot/rsrc/image/icon/fatcow/thumbnails/pdf60x45.png
new file mode 100644
index 0000000000..8a16eaf488
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diff --git a/webroot/rsrc/image/icon/fatcow/thumbnails/zip160x120.png b/webroot/rsrc/image/icon/fatcow/thumbnails/zip160x120.png
new file mode 100644
index 0000000000..fbe19e59f6
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diff --git a/webroot/rsrc/image/icon/fatcow/thumbnails/zip60x45.png b/webroot/rsrc/image/icon/fatcow/thumbnails/zip60x45.png
new file mode 100644
index 0000000000..c66416c318
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