Made some restructuring of the code for better readability.

Also fixed bug with the MD5_REGEX where the regexp was accually looking if there was a MD5 hash in the string and not that the string itself was a MD5 hash.

lib/gravatar.js

@@ -1,36 +1,43 @@
 var crypto = require('crypto')
   , querystring = require('querystring');
 
-var MD5_REGEX = /[0-9a-f]{32}/;
+var MD5_REGEX = /^[0-9a-f]{32}$/;
 
 var gravatar = module.exports = {
     url: function (email, options, protocol) {
-      email = email || 'unspecified';
-      email = email.trim().toLowerCase();
-      var hash = email.match(MD5_REGEX) ? email : crypto.createHash('md5').update(email).digest('hex');
       var baseURL;
-
       if(typeof protocol === 'undefined'){
         baseURL = "//www.gravatar.com/avatar/";
       } else {
         baseURL = protocol ? "https://s.gravatar.com/avatar/" : 'http://www.gravatar.com/avatar/';
       }
 
       var queryData = querystring.stringify(options);
-      var query = (queryData && "?" + queryData) || "";
+      var query = queryData ? ("?" + queryData) : "";
 
-      return baseURL + hash + query;
+      return baseURL + getHash(email) + query;
     },
     profile_url: function (email, options, https) {
-      email = email.trim().toLowerCase();
-      var hash = email.match(MD5_REGEX) ? email : crypto.createHash('md5').update(email).digest('hex');
-      var format = options != undefined && options.format != undefined ?  String(options.format) : 'json'
-      //delete options.format
-      if (options != undefined && options.format != undefined) delete options.format
+      var baseUrl = (typeof secure === 'undefined') ? "//www.gravatar.com/" : (secure ? "https://s.gravatar.com/" : "http://www.gravatar.com/");
+
+      //Default format is json, replace
+      var format = "json";
+      if(options != undefined && options.format != undefined){
+        format = options.format;
+        delete options.format;  //Delete so that it is not included in the querystring
+      }
+
       var baseURL = (https && "https://secure.gravatar.com/") || 'http://www.gravatar.com/';
+
       var queryData = querystring.stringify(options);
       var query = (queryData && "?" + queryData) || "";
 
-      return baseURL + hash + '.' + format + query;
+      return baseURL + getHash(email) + '.' + format + query;
     }
 };
+
+function getHash(email){
+  email = email || 'unspecified';
+  email = email.trim().toLowerCase();
+  return email.match(MD5_REGEX) ? email : crypto.createHash('md5').update(email).digest('hex');
+}