security - node.js - secure image file upload -

we had implement image uploader node.js project. framework using express.js did described here: http://howtonode.org/really-simple-file-uploads

but not sure how secure image uploader. did far is:

• checking file size
• checking extension , header
• rename file
• file accessible on special route , not in root folder

is enough? don't feel comfortable following line:

    // checking filesize, extension, headers     fs.readfile(req.files.displayimage.path, function (err, data) {         ...         ...         ...         // renaming file         // save file         ...         ...         ...     } 

is save read image way? afraid, there malicious code in req.files.displayimage.path. need add more checks or our checks sufficient? attack vectors offer attacker if use code described?

thank advices tschoartschi