Don't remove b64 src if it's the only attr that contains image

Readability.js

@@ -1809,12 +1809,29 @@ Readability.prototype = {
           return;
         }
 
+        // Make sure this element has other attributes which contains image.
+        // If it doesn't, then this src is important and shouldn't be removed.
+        var srcCouldBeRemoved = false;
+        for (var i = 0; i < elem.attributes.length; i++) {
+          var attr = elem.attributes[i];
+          if (attr.name === "src") {
+            continue;
+          }
+
+          if (/\.(jpg|jpeg|png|webp)/i.test(attr.value)) {
+            srcCouldBeRemoved = true;
+            break;
+          }
+        }
+
         // Here we assume if image is less than 100 bytes (or 133B after encoded to base64)
-        // it will be too small, therefore it might be placeholder image. 
-        var b64starts = elem.src.indexOf("base64,") + 7;
-        var b64length = elem.src.length - b64starts;
-        if (b64length < 133) {
-          elem.removeAttribute("src");
+        // it will be too small, therefore it might be placeholder image.
+        if (srcCouldBeRemoved) {
+          var b64starts = elem.src.search(/base64\s*/i) + 7;
+          var b64length = elem.src.length - b64starts;
+          if (b64length < 133) {
+            elem.removeAttribute("src");
+          }
         }
       }
 
@@ -1823,8 +1840,8 @@ Readability.prototype = {
         return;
       }
 
-      for (var i = 0; i < elem.attributes.length; i++) {
-        var attr = elem.attributes[i];
+      for (var j = 0; j < elem.attributes.length; j++) {
+        attr = elem.attributes[j];
         if (attr.name === "src" || attr.name === "srcset") {
           continue;
         }

test/test-pages/data-url-image/expected-metadata.json

@@ -0,0 +1,8 @@
+{
+  "title": "Document",
+  "byline": null,
+  "dir": null,
+  "excerpt": "Lorem ipsum dolor sit amet consectetur adipisicing elit. Natus eaque totam provident obcaecati nisi praesentium iusto velit fuga debitis quidem ut repellat corrupti, eligendi inventore quibusdam perspiciatis delectus omnis pariatur excepturi quasi fugit? A adipisci natus nostrum, qui aperiam, at culpa corrupti autem enim earum vitae. Nostrum et officiis facere ex recusandae tenetur, delectus odit provident soluta id perferendis ducimus quibusdam corporis rerum voluptatem architecto sequi beatae quod mollitia voluptatibus earum tempora inventore ut. Deserunt reprehenderit recusandae nostrum, eaque fuga cum, repellat, perspiciatis ducimus in non consequatur ratione. Sint rerum necessitatibus deleniti odio earum voluptatum eos modi ab dolor minus.",
+  "siteName": null,
+  "readerable": true
+}