diff --git a/core/modules/widgets/edit/editors/bitmapeditor.js b/core/modules/widgets/edit/editors/bitmapeditor.js
index 3d0ff2069..095e0ec54 100644
--- a/core/modules/widgets/edit/editors/bitmapeditor.js
+++ b/core/modules/widgets/edit/editors/bitmapeditor.js
@@ -12,8 +12,14 @@ A bitmap editor
 /*global $tw: false */
 "use strict";
 
+// Default images sizes
 var DEFAULT_IMAGE_WIDTH = 300,
-	DEFAULT_IMAGE_HEIGHT = 182;
+	DEFAULT_IMAGE_HEIGHT = 185;
+
+// The elements of the editor UI
+var DOM_CANVAS = 0,
+	DOM_WIDTH = 1,
+	DOM_HEIGHT = 2;
 
 var BitmapEditor = function(editWidget,tiddlerTitle,fieldName) {
 	this.editWidget = editWidget;
@@ -58,13 +64,39 @@ BitmapEditor.prototype.render = function() {
 			handlerObject: this,
 			handlerMethod: "handleMouseUpEvent"
 		}]
+	},{
+		type: "element",
+		tag: "input",
+		attributes: {
+			"class": {type: "string", value: "tw-edit-bitmapeditor-width"},
+			"type": {type: "string", value: "number"},
+			"value": {type: "string", value: ""}
+		},
+		events: [{
+			name: "change",
+			handlerObject: this,
+			handlerMethod: "handleWidthChangeEvent"
+		}]
+	},{
+		type: "element",
+		tag: "input",
+		attributes: {
+			"class": {type: "string", value: "tw-edit-bitmapeditor-height"},
+			"type": {type: "string", value: "number"},
+			"value": {type: "string", value: ""}
+		},
+		events: [{
+			name: "change",
+			handlerObject: this,
+			handlerMethod: "handleHeightChangeEvent"
+		}]
 	}];
 	this.editWidget.children = this.editWidget.renderer.renderTree.createRenderers(this.editWidget.renderer,children);
 };
 
 BitmapEditor.prototype.postRenderInDom = function() {
 	var tiddler = this.editWidget.renderer.renderTree.wiki.getTiddler(this.tiddlerTitle),
-		canvas = this.editWidget.renderer.domNode.firstChild,
+		canvas = this.getDomNode(DOM_CANVAS),
 		currImage = new Image();
 	// Set up event handlers for loading the image
 	var self = this;
@@ -74,6 +106,8 @@ BitmapEditor.prototype.postRenderInDom = function() {
 		// And also copy the current bitmap to the off-screen canvas
 		self.currCanvas = self.editWidget.renderer.renderTree.document.createElement("canvas");
 		self.initCanvas(self.currCanvas,currImage.width,currImage.height,currImage);
+		// Set the width and height input boxes
+		self.updateSize();
 	};
 	currImage.onerror = function() {
 		// Set the on-screen canvas size and clear it
@@ -81,6 +115,8 @@ BitmapEditor.prototype.postRenderInDom = function() {
 		// Set the off-screen canvas size and clear it
 		self.currCanvas = self.editWidget.renderer.renderTree.document.createElement("canvas");
 		self.initCanvas(self.currCanvas,DEFAULT_IMAGE_WIDTH,DEFAULT_IMAGE_HEIGHT);
+		// Set the width and height input boxes
+		self.updateSize();
 	}
 	// Get the current bitmap into an image object
 	currImage.src = "data:" + tiddler.fields.type + ";base64," + tiddler.fields.text;
@@ -98,6 +134,61 @@ BitmapEditor.prototype.initCanvas = function(canvas,width,height,image) {
 	}
 }
 
+BitmapEditor.prototype.getDomNode = function(index) {
+	return this.editWidget.renderer.domNode.childNodes[index];
+};
+
+/*
+** Update the input boxes with the actual size of the canvas
+*/
+BitmapEditor.prototype.updateSize = function() {
+	this.getDomNode(DOM_WIDTH).value = this.currCanvas.width;
+	this.getDomNode(DOM_HEIGHT).value = this.currCanvas.height;
+};
+
+/*
+** Change the size of the canvas, preserving the current image
+*/
+BitmapEditor.prototype.changeCanvasSize = function(newWidth,newHeight) {
+	// Create and size a new canvas
+	var newCanvas = this.editWidget.renderer.renderTree.document.createElement("canvas");
+	this.initCanvas(newCanvas,newWidth,newHeight);
+	// Copy the old image
+	var ctx = newCanvas.getContext("2d");
+	ctx.drawImage(this.currCanvas,0,0);
+	// Set the new canvas as the current one
+	this.currCanvas = newCanvas;
+	// Set the size of the onscreen canvas
+	var canvas = this.getDomNode(DOM_CANVAS);
+	canvas.width = newWidth;
+	canvas.height = newHeight;
+	// Paint the onscreen canvas with the offscreen canvas
+	ctx = canvas.getContext("2d");
+	ctx.drawImage(this.currCanvas,0,0);
+};
+
+BitmapEditor.prototype.handleWidthChangeEvent = function(event) {
+	// Get the new width
+	var newWidth = parseInt(this.getDomNode(DOM_WIDTH).value,10);
+	// Update if necessary
+	if(newWidth > 0 && newWidth !== this.currCanvas.width) {
+		this.changeCanvasSize(newWidth,this.currCanvas.height);
+	}
+	// Update the input controls
+	this.updateSize();
+};
+
+BitmapEditor.prototype.handleHeightChangeEvent = function(event) {
+	// Get the new width
+	var newHeight = parseInt(this.getDomNode(DOM_HEIGHT).value,10);
+	// Update if necessary
+	if(newHeight > 0 && newHeight !== this.currCanvas.height) {
+		this.changeCanvasSize(this.currCanvas.width,newHeight);
+	}
+	// Update the input controls
+	this.updateSize();
+};
+
 BitmapEditor.prototype.handleTouchStartEvent = function(event) {
 	this.brushDown = true;
 	this.strokeStart(event.touches[0].clientX,event.touches[0].clientY);
@@ -155,7 +246,7 @@ BitmapEditor.prototype.handleMouseUpEvent = function(event) {
 };
 
 BitmapEditor.prototype.adjustCoordinates = function(x,y) {
-	var canvas = this.editWidget.renderer.domNode.firstChild,
+	var canvas = this.getDomNode(DOM_CANVAS),
 		canvasRect = canvas.getBoundingClientRect(),
 		scale = canvas.width/canvasRect.width;
 	return {x: (x - canvasRect.left) * scale, y: (y - canvasRect.top) * scale};
@@ -167,7 +258,7 @@ BitmapEditor.prototype.strokeStart = function(x,y) {
 };
 
 BitmapEditor.prototype.strokeMove = function(x,y) {
-	var canvas = this.editWidget.renderer.domNode.firstChild,
+	var canvas = this.getDomNode(DOM_CANVAS),
 		ctx = canvas.getContext("2d"),
 		t;
 	// Add the new position to the end of the stroke
@@ -193,7 +284,7 @@ BitmapEditor.prototype.strokeMove = function(x,y) {
 
 BitmapEditor.prototype.strokeEnd = function() {
 	// Copy the bitmap to the off-screen canvas
-	var canvas = this.editWidget.renderer.domNode.firstChild,
+	var canvas = this.getDomNode(DOM_CANVAS),
 		ctx = this.currCanvas.getContext("2d");
 	ctx.drawImage(canvas,0,0);
 	// Save the image into the tiddler
@@ -204,7 +295,7 @@ BitmapEditor.prototype.saveChanges = function() {
 	var tiddler = this.editWidget.renderer.renderTree.wiki.getTiddler(this.tiddlerTitle);
 	if(tiddler) {
 		// data URIs look like "data:<type>;base64,<text>"
-		var dataURL = this.editWidget.renderer.domNode.firstChild.toDataURL(tiddler.fields.type,1.0),
+		var dataURL = this.getDomNode(DOM_CANVAS).toDataURL(tiddler.fields.type,1.0),
 			posColon = dataURL.indexOf(":"),
 			posSemiColon = dataURL.indexOf(";"),
 			posComma = dataURL.indexOf(","),
diff --git a/themes/tiddlywiki/snowwhite/base.tid b/themes/tiddlywiki/snowwhite/base.tid
index 5843aa729..0975ce0c9 100644
--- a/themes/tiddlywiki/snowwhite/base.tid
+++ b/themes/tiddlywiki/snowwhite/base.tid
@@ -453,6 +453,14 @@ canvas.tw-edit-bitmapeditor  {
 	-ms-user-select: none;
 }
 
+.tw-edit-bitmapeditor-width {
+	display: block;
+}
+
+.tw-edit-bitmapeditor-height {
+	display: block;
+}
+
 /*
 ** Tiddler edit mode
 */