code: public EmbedBuilder setImage(String url)
      {
          if (url == null)
          {
              this.image = null;
          }
          else
          {
              urlCheck(url);
              this.image = new MessageEmbed.ImageInfo(url, null, 0, 0);
          }
          return this;
      }
docs: Sets the Image of the embed.
  
  <p><b><a href="http://i.imgur.com/2hzuHFJ.png">Example</a></b>
  
  <p><b>Uploading images with Embeds</b>
  <br>When uploading an <u>image</u>
  (using {@link net.dv8tion.jda.core.entities.MessageChannel#sendFile(java.io.File, net.dv8tion.jda.core.entities.Message) MessageChannel.sendFile(...)})
  you can reference said image using the specified filename as URI {@code attachment://filename.ext}.
  
  <p><u>Example</u>
  <pre><code>
  MessageChannel channel; // = reference of a MessageChannel
  MessageBuilder message = new MessageBuilder();
  EmbedBuilder embed = new EmbedBuilder();
  InputStream file = new URL("https://http.cat/500").openStream();
  embed.setImage("attachment://cat.png") // we specify this in sendFile as "cat.png"
  .setDescription("This is a cute cat :3");
  message.setEmbed(embed.build());
  channel.sendFile(file, "cat.png", message.build()).queue();
  </code></pre>
  
  @param  url
  the url of the image of the embed
  
  @throws java.lang.IllegalArgumentException
  <ul>
  <li>If the length of {@code url} is longer than {@link net.dv8tion.jda.core.entities.MessageEmbed#URL_MAX_LENGTH}.</li>
  <li>If the provided {@code url} is not a properly formatted http or https url.</li>
  </ul>
  
  @return the builder after the image has been set
  
  @see    net.dv8tion.jda.core.entities.MessageChannel#sendFile(java.io.File, String, net.dv8tion.jda.core.entities.Message) MessageChannel.sendFile(...)