Add inline Droplr previews to Propane for mac. Go to the propane application, command click and choose show package contents. Click Contents > Resources > enhancer.js. Add the code to the bottom of this file inside of window.propane. Just know that when you update propane this file will get overwritten and you'll have to do this again.

gistfile1.txt

/* 
Display Droplr images inline.

This responder illustrates using Propane's requestJSON service to request 
JSON from remote (non-authenticated) servers and have the results passed
to a callback of your choosing.
*/

var displayDroplrImages = true;

if (displayDroplrImages) {

  Campfire.DroplrExpander = Class.create({
    initialize: function(chat) {
      this.chat = chat;
      var messages = this.chat.transcript.messages;
      for (var i = 0; i < messages.length; i++) {
        this.detectDroplrURL(messages[i]);
      }
    },

    detectDroplrURL: function(message) {
      /* we are going to use the messageID to uniquely identify our requestJSON request
         so we don't check pending messages */
      if (!message.pending() && message.kind === 'text') {
        var links = message.bodyElement().select('a:not(image)');
        if (links.length != 1) {
          return;
        }
        var href = links[0].getAttribute('href');
    
        var match = href.match(/^http?:\/\/d.pr\/([A-Za-z0-9]+)\/([A-Za-z0-9]+)\/?$/);
        if (!match) return;
    
    //alert(match[2]);
    
        //var url = "http://droplr-json.heroku.com/"+match[2];
        var url = "http://dev.socialdesignhouse.com/droplr/droplr-json.php?type="+match[1]+"&drop="+match[2];
    
    window.propane.requestJSON(message.id(), url, 'window.chat.droplrexpander', 'onEmbedDataLoaded', 'onEmbedDataFailed');
      }
    },

    onEmbedDataLoaded: function(messageID, data) {
  //alert(data.image);
      var message = window.chat.transcript.getMessageById(messageID);
      if (!message) return;
      if (data['type'] === 'image') {
        var imageURL = data.src;
        message.resize((function() {
          message.bodyCell.insert({bottom: '<div style="width:100%; margin-top:5px; padding-top: 5px; border-top:1px dotted #ccc;"><a href="'+imageURL+'" class="image loading" target="_blank">' + '<img src="'+imageURL+'" onload="$dispatch(&quot;inlineImageLoaded&quot;, this)" onerror="$dispatch(&quot;inlineImageLoadFailed&quot;, this)" /></a></div>'});
        }).bind(this));
      }
    },

    onEmbedDataFailed: function(messageID) {
      /* No cleanup required, we only alter the HTML after we get back a succesful load from the data */
    },

    onMessagesInsertedBeforeDisplay: function(messages) {
      for (var i = 0; i < messages.length; i++) {
        this.detectDroplrURL(messages[i]);
      }
    },

    onMessageAccepted: function(message, messageID) {
      this.detectDroplrURL(message);
    }
  });

  Campfire.Responders.push("DroplrExpander");
  window.chat.installPropaneResponder("DroplrExpander", "droplrexpander");
}