diff --git a/openseadragon.sublime-project b/openseadragon.sublime-project
index 1d6484e7..4feb36d8 100644
--- a/openseadragon.sublime-project
+++ b/openseadragon.sublime-project
@@ -8,7 +8,8 @@
                 "*.sublime-workspace"
             ],
             "folder_exclude_patterns": [
-                "node_modules"
+                "node_modules",
+                "coverage"
             ]
         }
     ],
@@ -17,5 +18,5 @@
         "tab_size": 4,
         "translate_tabs_to_spaces": true,
         "trim_trailing_white_space_on_save": true
-    }   
+    }
 }
diff --git a/src/tiledimage.js b/src/tiledimage.js
index 40726dbd..c345765b 100644
--- a/src/tiledimage.js
+++ b/src/tiledimage.js
@@ -87,6 +87,7 @@ $.TiledImage = function( options ) {
 
     // Ratio of zoomable image height to width.
     this.normHeight = options.source.dimensions.y / options.source.dimensions.x;
+    this.contentAspectX = options.source.dimensions.x / options.source.dimensions.y;
 
     if ( options.width ) {
         this._setScale(options.width);
@@ -183,6 +184,122 @@ $.extend($.TiledImage.prototype, $.EventSource.prototype, /** @lends OpenSeadrag
         return new $.Point(this.source.dimensions.x, this.source.dimensions.y);
     },
 
+    /**
+     * Translates from OpenSeadragon viewer coordinate system to image coordinate system.
+     * This method can be called either by passing X,Y coordinates or an
+     * OpenSeadragon.Point
+     * @function
+     * @param {OpenSeadragon.Point} viewerX the point in viewport coordinate system.
+     * @param {Number} viewerX X coordinate in viewport coordinate system.
+     * @param {Number} viewerY Y coordinate in viewport coordinate system.
+     * @return {OpenSeadragon.Point} a point representing the coordinates in the image.
+     */
+    viewportToImageCoordinates: function( viewerX, viewerY ) {
+        if ( arguments.length == 1 ) {
+            //they passed a point instead of individual components
+            return this.viewportToImageCoordinates( viewerX.x, viewerX.y );
+        }
+
+        var contentSize = this.source.dimensions;
+        return new $.Point((viewerX - this._worldX) * (contentSize.x / this._scale),
+            (viewerY - this._worldY) * ((contentSize.y * this.contentAspectX) / this._scale));
+    },
+
+    /**
+     * Translates from image coordinate system to OpenSeadragon viewer coordinate system
+     * This method can be called either by passing X,Y coordinates or an
+     * OpenSeadragon.Point
+     * @function
+     * @param {OpenSeadragon.Point} imageX the point in image coordinate system.
+     * @param {Number} imageX X coordinate in image coordinate system.
+     * @param {Number} imageY Y coordinate in image coordinate system.
+     * @return {OpenSeadragon.Point} a point representing the coordinates in the viewport.
+     */
+    imageToViewportCoordinates: function( imageX, imageY ) {
+        if ( arguments.length == 1 ) {
+            //they passed a point instead of individual components
+            return this.imageToViewportCoordinates( imageX.x, imageX.y );
+        }
+
+        var contentSize = this.source.dimensions;
+        return new $.Point(this._worldX + ((imageX / contentSize.x) * this._scale),
+            this._worldY + ((imageY / contentSize.y / this.contentAspectX) * this._scale));
+    },
+
+    /**
+     * Translates from a rectangle which describes a portion of the image in
+     * pixel coordinates to OpenSeadragon viewport rectangle coordinates.
+     * This method can be called either by passing X,Y,width,height or an
+     * OpenSeadragon.Rect
+     * @function
+     * @param {OpenSeadragon.Rect} imageX the rectangle in image coordinate system.
+     * @param {Number} imageX the X coordinate of the top left corner of the rectangle
+     * in image coordinate system.
+     * @param {Number} imageY the Y coordinate of the top left corner of the rectangle
+     * in image coordinate system.
+     * @param {Number} pixelWidth the width in pixel of the rectangle.
+     * @param {Number} pixelHeight the height in pixel of the rectangle.
+     */
+    imageToViewportRectangle: function( imageX, imageY, pixelWidth, pixelHeight ) {
+        var coordA,
+            coordB,
+            rect;
+        if( arguments.length == 1 ) {
+            //they passed a rectangle instead of individual components
+            rect = imageX;
+            return this.imageToViewportRectangle(
+                rect.x, rect.y, rect.width, rect.height
+            );
+        }
+        coordA = this.imageToViewportCoordinates(
+            imageX, imageY
+        );
+        coordB = this.imageToViewportCoordinates(
+            imageX + pixelWidth, imageY + pixelHeight
+        );
+        return new $.Rect(
+            coordA.x,
+            coordA.y,
+            coordB.x - coordA.x,
+            coordB.y - coordA.y
+        );
+    },
+
+    /**
+     * Translates from a rectangle which describes a portion of
+     * the viewport in point coordinates to image rectangle coordinates.
+     * This method can be called either by passing X,Y,width,height or an
+     * OpenSeadragon.Rect
+     * @function
+     * @param {OpenSeadragon.Rect} viewerX the rectangle in viewport coordinate system.
+     * @param {Number} viewerX the X coordinate of the top left corner of the rectangle
+     * in viewport coordinate system.
+     * @param {Number} imageY the Y coordinate of the top left corner of the rectangle
+     * in viewport coordinate system.
+     * @param {Number} pointWidth the width of the rectangle in viewport coordinate system.
+     * @param {Number} pointHeight the height of the rectangle in viewport coordinate system.
+     */
+    viewportToImageRectangle: function( viewerX, viewerY, pointWidth, pointHeight ) {
+        var coordA,
+            coordB,
+            rect;
+        if ( arguments.length == 1 ) {
+            //they passed a rectangle instead of individual components
+            rect = viewerX;
+            return this.viewportToImageRectangle(
+                rect.x, rect.y, rect.width, rect.height
+            );
+        }
+        coordA = this.viewportToImageCoordinates( viewerX, viewerY );
+        coordB = this.viewportToImageCoordinates(viewerX + pointWidth, viewerY + pointHeight);
+        return new $.Rect(
+            coordA.x,
+            coordA.y,
+            coordB.x - coordA.x,
+            coordB.y - coordA.y
+        );
+    },
+
     /**
      * Sets the TiledImage's position in the world.
      * @param {OpenSeadragon.Point} position - The new position, in world coordinates.
diff --git a/src/viewport.js b/src/viewport.js
index 167e0eca..c56ef7f0 100644
--- a/src/viewport.js
+++ b/src/viewport.js
@@ -942,6 +942,7 @@ $.Viewport.prototype = /** @lends OpenSeadragon.Viewport.prototype */{
      * Translates from OpenSeadragon viewer coordinate system to image coordinate system.
      * This method can be called either by passing X,Y coordinates or an
      * OpenSeadragon.Point
+     * Note: not accurate with multi-image; use TiledImage.viewportToImageCoordinates instead.
      * @function
      * @param {OpenSeadragon.Point} viewerX the point in viewport coordinate system.
      * @param {Number} viewerX X coordinate in viewport coordinate system.
@@ -954,6 +955,10 @@ $.Viewport.prototype = /** @lends OpenSeadragon.Viewport.prototype */{
             return this.viewportToImageCoordinates( viewerX.x, viewerX.y );
         }
 
+        if (this.viewer && this.viewer.world.getItemCount() > 1) {
+            $.console.error('[Viewport.viewportToImageCoordinates] is not accurate with multi-image; use TiledImage.viewportToImageCoordinates instead.');
+        }
+
         var scale = this.homeBounds.width;
         return new $.Point((viewerX - this.homeBounds.x) * (this.contentSize.x / scale),
             (viewerY - this.homeBounds.y) * ((this.contentSize.y * this.contentAspectX) / scale));
@@ -963,6 +968,7 @@ $.Viewport.prototype = /** @lends OpenSeadragon.Viewport.prototype */{
      * Translates from image coordinate system to OpenSeadragon viewer coordinate system
      * This method can be called either by passing X,Y coordinates or an
      * OpenSeadragon.Point
+     * Note: not accurate with multi-image; use TiledImage.imageToViewportCoordinates instead.
      * @function
      * @param {OpenSeadragon.Point} imageX the point in image coordinate system.
      * @param {Number} imageX X coordinate in image coordinate system.
@@ -975,6 +981,10 @@ $.Viewport.prototype = /** @lends OpenSeadragon.Viewport.prototype */{
             return this.imageToViewportCoordinates( imageX.x, imageX.y );
         }
 
+        if (this.viewer && this.viewer.world.getItemCount() > 1) {
+            $.console.error('[Viewport.imageToViewportCoordinates] is not accurate with multi-image; use TiledImage.imageToViewportCoordinates instead.');
+        }
+
         var scale = this.homeBounds.width;
         return new $.Point(this.homeBounds.x + ((imageX / this.contentSize.x) * scale),
             this.homeBounds.y + ((imageY / this.contentSize.y / this.contentAspectX) * scale));
@@ -985,6 +995,7 @@ $.Viewport.prototype = /** @lends OpenSeadragon.Viewport.prototype */{
      * pixel coordinates to OpenSeadragon viewport rectangle coordinates.
      * This method can be called either by passing X,Y,width,height or an
      * OpenSeadragon.Rect
+     * Note: not accurate with multi-image; use TiledImage.imageToViewportRectangle instead.
      * @function
      * @param {OpenSeadragon.Rect} imageX the rectangle in image coordinate system.
      * @param {Number} imageX the X coordinate of the top left corner of the rectangle
@@ -1005,6 +1016,7 @@ $.Viewport.prototype = /** @lends OpenSeadragon.Viewport.prototype */{
                 rect.x, rect.y, rect.width, rect.height
             );
         }
+
         coordA = this.imageToViewportCoordinates(
             imageX, imageY
         );
@@ -1024,6 +1036,7 @@ $.Viewport.prototype = /** @lends OpenSeadragon.Viewport.prototype */{
      * the viewport in point coordinates to image rectangle coordinates.
      * This method can be called either by passing X,Y,width,height or an
      * OpenSeadragon.Rect
+     * Note: not accurate with multi-image; use TiledImage.viewportToImageRectangle instead.
      * @function
      * @param {OpenSeadragon.Rect} viewerX the rectangle in viewport coordinate system.
      * @param {Number} viewerX the X coordinate of the top left corner of the rectangle
@@ -1044,6 +1057,7 @@ $.Viewport.prototype = /** @lends OpenSeadragon.Viewport.prototype */{
                 rect.x, rect.y, rect.width, rect.height
             );
         }
+
         coordA = this.viewportToImageCoordinates( viewerX, viewerY );
         coordB = this.viewportToImageCoordinates(viewerX + pointWidth, viewerY + pointHeight);
         return new $.Rect(
@@ -1057,6 +1071,7 @@ $.Viewport.prototype = /** @lends OpenSeadragon.Viewport.prototype */{
     /**
      * Convert pixel coordinates relative to the viewer element to image
      * coordinates.
+     * Note: not accurate with multi-image.
      * @param {OpenSeadragon.Point} pixel
      * @returns {OpenSeadragon.Point}
      */
@@ -1068,6 +1083,7 @@ $.Viewport.prototype = /** @lends OpenSeadragon.Viewport.prototype */{
     /**
      * Convert pixel coordinates relative to the image to
      * viewer element coordinates.
+     * Note: not accurate with multi-image.
      * @param {OpenSeadragon.Point} pixel
      * @returns {OpenSeadragon.Point}
      */
@@ -1078,6 +1094,7 @@ $.Viewport.prototype = /** @lends OpenSeadragon.Viewport.prototype */{
 
     /**
      * Convert pixel coordinates relative to the window to image coordinates.
+     * Note: not accurate with multi-image.
      * @param {OpenSeadragon.Point} pixel
      * @returns {OpenSeadragon.Point}
      */
@@ -1089,6 +1106,7 @@ $.Viewport.prototype = /** @lends OpenSeadragon.Viewport.prototype */{
 
     /**
      * Convert image coordinates to pixel coordinates relative to the window.
+     * Note: not accurate with multi-image.
      * @param {OpenSeadragon.Point} pixel
      * @returns {OpenSeadragon.Point}
      */
@@ -1146,13 +1164,18 @@ $.Viewport.prototype = /** @lends OpenSeadragon.Viewport.prototype */{
      * 1 means original image size, 0.5 half size...
      * Viewport zoom: ratio of the displayed image's width to viewport's width.
      * 1 means identical width, 2 means image's width is twice the viewport's width...
+     * Note: not accurate with multi-image.
      * @function
      * @param {Number} viewportZoom The viewport zoom
      * target zoom.
      * @returns {Number} imageZoom The image zoom
      */
     viewportToImageZoom: function( viewportZoom ) {
-        var imageWidth = this.viewer.source.dimensions.x;
+        if (this.viewer && this.viewer.world.getItemCount() > 1) {
+            $.console.error('[Viewport.viewportToImageZoom] is not accurate with multi-image.');
+        }
+
+        var imageWidth = this.contentSize.x;
         var containerWidth = this._containerInnerSize.x;
         var scale = this.homeBounds.width;
         var viewportToImageZoomRatio = (containerWidth / imageWidth) * scale;
@@ -1165,13 +1188,18 @@ $.Viewport.prototype = /** @lends OpenSeadragon.Viewport.prototype */{
      * 1 means original image size, 0.5 half size...
      * Viewport zoom: ratio of the displayed image's width to viewport's width.
      * 1 means identical width, 2 means image's width is twice the viewport's width...
+     * Note: not accurate with multi-image.
      * @function
      * @param {Number} imageZoom The image zoom
      * target zoom.
      * @returns {Number} viewportZoom The viewport zoom
      */
     imageToViewportZoom: function( imageZoom ) {
-        var imageWidth = this.viewer.source.dimensions.x;
+        if (this.viewer && this.viewer.world.getItemCount() > 1) {
+            $.console.error('[Viewport.imageToViewportZoom] is not accurate with multi-image.');
+        }
+
+        var imageWidth = this.contentSize.x;
         var containerWidth = this._containerInnerSize.x;
         var scale = this.homeBounds.width;
         var viewportToImageZoomRatio = (imageWidth / containerWidth) / scale;