Improve getting deviatnart url from page

fix #2366

app/logical/sources/strategies/deviant_art.rb

@@ -47,6 +47,11 @@ module Sources
       end
 
       def get_image_url_from_page(page)
+        image = page.search("div.dev-view-deviation img.dev-content-full")
+
+        if image.any?
+          image[0]["src"]
+        else
           download_link = page.link_with(:class => /dev-page-download/)
 
           if download_link
@@ -55,6 +60,7 @@ module Sources
             nil
           end
         end
+      end
 
       def normalized_url
         @normalized_url ||= begin