diff --git a/README b/README
index b65a08d425..0bf1319c6d 100644
--- a/README
+++ b/README
@@ -262,13 +262,16 @@ especially if you've previously installed PHP/MySQL packages.
    that user's default group instead. As a last resort, you can create
    a new group like "mublog" and add the Web server's user to the group.
 
-4. You should also take this moment to make your avatar subdirectory
-   writeable by the Web server. An insecure way to do this is:
+4. You should also take this moment to make your avatar, background, and
+   file subdirectories writeable by the Web server. An insecure way to do
+   this is:
 
    	  chmod a+w /var/www/mublog/avatar
+   	  chmod a+w /var/www/mublog/background
+   	  chmod a+w /var/www/mublog/file
 
-   You can also make the avatar directory writeable by the Web server
-   group, as noted above.
+   You can also make the avatar, background, and file directories
+   writeable by the Web server group, as noted above.
 
 5. Create a database to hold your microblog data. Something like this
    should work:
diff --git a/install.php b/install.php
index bae296a350..1d3a531c5a 100644
--- a/install.php
+++ b/install.php
@@ -70,17 +70,16 @@ function checkPrereqs()
 	     $pass = false;
 	}
 
-	if (!is_writable(INSTALLDIR.'/avatar/')) {
-         ?><p class="error">Cannot write avatar directory: <code><?php echo INSTALLDIR; ?>/avatar/</code></p>
-	       <p>On your server, try this command: <code>chmod a+w <?php echo INSTALLDIR; ?>/avatar/</code></p>
-         <?
-	     $pass = false;
-	}
-	if (!is_writable(INSTALLDIR.'/background/')) {
-         ?><p class="error">Cannot write background directory: <code><?php echo INSTALLDIR; ?>/background/</code></p>
-	       <p>On your server, try this command: <code>chmod a+w <?php echo INSTALLDIR; ?>/background/</code></p>
-         <?
-	     $pass = false;
+	// Check the subdirs used for file uploads
+	$fileSubdirs = array('avatar', 'background', 'file');
+	foreach ($fileSubdirs as $fileSubdir) {
+		$fileFullPath = INSTALLDIR."/$fileSubdir/";
+		if (!is_writable($fileFullPath)) {
+    	     ?><p class="error">Cannot write <?php echo $fileSubdir; ?> directory: <code><?php echo $fileFullPath; ?></code></p>
+		       <p>On your server, try this command: <code>chmod a+w <?php echo $fileFullPath; ?></code></p>
+    	     <?
+		     $pass = false;
+		}
 	}
 
 	return $pass;