diff --git a/app/assets/javascripts/channels/concurrent_editing.js b/app/assets/javascripts/channels/concurrent_editing.js
index f93e01e45..872022784 100644
--- a/app/assets/javascripts/channels/concurrent_editing.js
+++ b/app/assets/javascripts/channels/concurrent_editing.js
@@ -1,6 +1,10 @@
 /* Handles all the frontend interactions with action cable and the server.  */
 
-App.concurrent_editing = App.cable.subscriptions.create("ConcurrentEditingChannel", {
+App.concurrent_editing = App.cable.subscriptions.create(
+    {
+        channel: "ConcurrentEditingChannel",
+        mapSlug: window.location.href.split("/").pop()
+    }, {
   connected: function() {
     // Called when the subscription is ready for use on the server
   },
@@ -11,7 +15,7 @@ App.concurrent_editing = App.cable.subscriptions.create("ConcurrentEditingChanne
 
   received: function(data) {
     // Called when there's incoming data on the websocket for this channel
-    window.mapKnitter.synchronizeData(data.changes);
+    window.mapknitter.synchronizeData(data.changes);
   },
 
   speak: function(changes) {
@@ -20,7 +24,8 @@ App.concurrent_editing = App.cable.subscriptions.create("ConcurrentEditingChanne
     *  which is responsible for broadcasting the updated warpables
     *  to all the user's connected to the concurrent_editing channel. */
     return this.perform("sync", {
-        changes: changes
+        changes: changes,
+        map_slug: window.location.href.split("/").pop()
     });
   }
 });
diff --git a/app/assets/javascripts/mapknitter/Map.js b/app/assets/javascripts/mapknitter/Map.js
index c7659757e..a7051a25a 100644
--- a/app/assets/javascripts/mapknitter/Map.js
+++ b/app/assets/javascripts/mapknitter/Map.js
@@ -405,11 +405,123 @@ MapKnitter.Map = MapKnitter.Class.extend({
           corners [2] = y;
           corners [3] = x;
 
-          console.log(corners);
-
           layer = layers.filter(l => l._url==warpable.srcmedium)[0];
-          layer.setCorners(corners);
+
+          if(layer == null || layer == undefined) {
+              window.mapknitter.synchronizeNewAddedImage(warpable);
+          } else {
+              layer.setCorners(corners);
+              var index = layers.indexOf(layer);
+              if (index > -1) {
+                  layers.splice(index, 1);
+              }
+          }
       });
+
+      // remove images if deleted from any user's browser
+      layers.forEach(function(layer) {
+          edit = layer.editing
+          edit._removeToolbar();
+          edit.disable();
+          // remove from Leaflet map:
+          map.removeLayer(layer);
+          // remove from sidebar too:
+          $('#warpable-' + layer.warpable_id).remove();
+      });
+  },
+
+  synchronizeNewAddedImage: function(warpable) {
+      var wn = warpable.nodes;
+      bounds = [];
+
+      // only already-placed images:
+      if (wn.length > 0) {
+          var downloadEl = $('.img-download-' + warpable.id),
+              imgEl = $('#full-img-' + warpable.id);
+
+          downloadEl.click(function () {
+              downloadEl.html('<i class="fa fa-circle-o-notch fa-spin"></i>');
+
+              imgEl[0].onload = function () {
+                  var height = imgEl.height(),
+                      width = imgEl.width(),
+                      nw = map.latLngToContainerPoint(wn[0]),
+                      ne = map.latLngToContainerPoint(wn[1]),
+                      se = map.latLngToContainerPoint(wn[2]),
+                      sw = map.latLngToContainerPoint(wn[3]),
+                      offsetX = nw.x,
+                      offsetY = nw.y,
+                      displayedWidth = $('#warpable-img-' + warpable.id).width(),
+                      ratio = width / displayedWidth;
+
+                  nw.x -= offsetX;
+                  ne.x -= offsetX;
+                  se.x -= offsetX;
+                  sw.x -= offsetX;
+
+                  nw.y -= offsetY;
+                  ne.y -= offsetY;
+                  se.y -= offsetY;
+                  sw.y -= offsetY;
+
+                  warpWebGl(
+                      'full-img-' + warpable.id,
+                      [0, 0, width, 0, width, height, 0, height],
+                      [nw.x, nw.y, ne.x, ne.y, se.x, se.y, sw.x, sw.y],
+                      true // trigger download
+                  )
+
+                  downloadEl.html('<i class="fa fa-download"></i>');
+              }
+
+              imgEl[0].src = $('.img-download-' + warpable.id).attr('data-image');
+          });
+
+          var corners = [
+              L.latLng(wn[0].lat, wn[0].lon),
+              L.latLng(wn[1].lat, wn[1].lon),
+              L.latLng(wn[3].lat, wn[3].lon),
+              L.latLng(wn[2].lat, wn[2].lon)
+          ];
+
+          var img = L.distortableImageOverlay(warpable.srcmedium, {
+              corners: corners,
+              mode: 'lock'
+          }).addTo(map);
+
+          var customExports = mapknitter.customExportAction();
+          var imgGroup = L.distortableCollection({
+              actions: [customExports]
+          }).addTo(map);
+
+          imgGroup.addLayer(img);
+
+          /**
+           * TODO: toolbar may still appear outside of frame. Create a getter for toolbar corners in LDI and then include them in this calculation
+           */
+          bounds = bounds.concat(corners);
+          var newImgBounds = L.latLngBounds(corners);
+
+          if (!map._initialBounds.contains(newImgBounds) && !map._initialBounds.equals(newImgBounds)) {
+              map._initialBounds.extend(newImgBounds);
+              mapknitter._map.flyToBounds(map._initialBounds);
+          }
+
+          images.push(img);
+          img.warpable_id = warpable.id;
+
+          if (!mapknitter.readOnly) {
+              L.DomEvent.on(img._image, {
+                  click: mapknitter.selectImage,
+                  dblclick: mapknitter.dblClickImage,
+                  load: mapknitter.setupToolbar
+              }, img);
+
+              L.DomEvent.on(imgGroup, 'layeradd', mapknitter.setupEvents, img);
+          }
+
+          img.editing.disable()
+      }
   },
 
   saveImageIfChanged: function () {
@@ -434,7 +546,7 @@ MapKnitter.Map = MapKnitter.Class.extend({
   saveImage: function () {
     var img = this;
     img._corner_state = JSON.stringify(img._corners); // reset change state string:
-    $.ajax('/images', { // send save request
+    $.ajax('/images/'+img.warpable_id, { // send save request
       type: 'PATCH',
       data: {
         warpable_id: img.warpable_id,
@@ -474,6 +586,9 @@ MapKnitter.Map = MapKnitter.Class.extend({
           beforeSend: function (e) {
             $('.mk-save').removeClass('fa-check-circle fa-times-circle fa-green fa-red').addClass('fa-spinner fa-spin')
           },
+          success: function(data) {
+              App.concurrent_editing.speak(data);
+          },
           complete: function (e) {
             $('.mk-save').removeClass('fa-spinner fa-spin').addClass('fa-check-circle fa-green')
             // disable interactivity:
diff --git a/app/channels/concurrent_editing_channel.rb b/app/channels/concurrent_editing_channel.rb
index 79991c3b1..35ea0bb7c 100644
--- a/app/channels/concurrent_editing_channel.rb
+++ b/app/channels/concurrent_editing_channel.rb
@@ -3,7 +3,7 @@ class ConcurrentEditingChannel < ApplicationCable::Channel
 
   def subscribed
     # Called first to connect user to the channel.
-    stream_from "concurrent_editing_channel"
+    stream_from "concurrent_editing_channel:#{params[:mapSlug]}"
   end
 
   def unsubscribed
@@ -12,6 +12,6 @@ def unsubscribed
 
   def sync(changes)
     # Responsible for broadcasting the updated warpables or simply images to the user's connected on this channel.
-    ActionCable.server.broadcast 'concurrent_editing_channel', changes
+    ActionCable.server.broadcast "concurrent_editing_channel:#{changes['map_slug']}", changes
   end
 end
diff --git a/app/controllers/images_controller.rb b/app/controllers/images_controller.rb
index 30213e913..88300b8db 100644
--- a/app/controllers/images_controller.rb
+++ b/app/controllers/images_controller.rb
@@ -92,10 +92,7 @@ def update
       @warpable.locked = params[:locked]
       @warpable.cm_per_pixel = @warpable.get_cm_per_pixel
       @warpable.save
-      respond_to do |format|
-        format.html { render html: 'success' }
-        format.json { render json: @warpable.map.fetch_map_data }
-      end
+      render json: @warpable.map.fetch_map_data
     else
       render plain: 'You must be logged in to update the image, unless the map is anonymous.'
     end
@@ -114,7 +111,7 @@ def destroy
       @warpable.destroy
       respond_to do |format|
         format.html { redirect_to @warpable.map }
-        format.json { render json: @warpable }
+        format.json { render json: @warpable.map.fetch_map_data }
       end
     else
       flash[:error] = 'You must be logged in to delete images.'
diff --git a/test/controllers/images_controller_test.rb b/test/controllers/images_controller_test.rb
index 042096f72..41ae79767 100644
--- a/test/controllers/images_controller_test.rb
+++ b/test/controllers/images_controller_test.rb
@@ -62,7 +62,7 @@ def fetch_in_production
     points = "-71.39,41.83:-71.39,41.83:-71.39,41.83:-71.39,41.83"
     patch :update, params: { id: @map.id, warpable_id: @warp.id, locked: false, points: points}
     assert_not_nil @warp.nodes
-    assert_equal "text/html", response.content_type
+    assert_equal "application/json", response.content_type
     assert_response :success
   end