diff --git a/src/applications/files/controller/PhabricatorFileViewController.php b/src/applications/files/controller/PhabricatorFileViewController.php
--- a/src/applications/files/controller/PhabricatorFileViewController.php
+++ b/src/applications/files/controller/PhabricatorFileViewController.php
@@ -311,7 +311,7 @@
       $file->getStorageHandle());
 
     $custom_alt = $file->getCustomAltText();
-    if (strlen($custom_alt)) {
+    if (phutil_nonempty_string($custom_alt)) {
       $finfo->addProperty(pht('Custom Alt Text'), $custom_alt);
     }
 
diff --git a/src/applications/files/document/render/PhabricatorDocumentRenderingEngine.php b/src/applications/files/document/render/PhabricatorDocumentRenderingEngine.php
--- a/src/applications/files/document/render/PhabricatorDocumentRenderingEngine.php
+++ b/src/applications/files/document/render/PhabricatorDocumentRenderingEngine.php
@@ -60,12 +60,12 @@
     }
 
     $encode_setting = $request->getStr('encode');
-    if (strlen($encode_setting)) {
+    if (phutil_nonempty_string($encode_setting)) {
       $engine->setEncodingConfiguration($encode_setting);
     }
 
     $highlight_setting = $request->getStr('highlight');
-    if (strlen($highlight_setting)) {
+    if (phutil_nonempty_string($highlight_setting)) {
       $engine->setHighlightingConfiguration($highlight_setting);
     }
 
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
@@ -1278,7 +1278,7 @@
   public function getAltText() {
     $alt = $this->getCustomAltText();
 
-    if (strlen($alt)) {
+    if (phutil_nonempty_string($alt)) {
       return $alt;
     }