diff --git a/ui/base.js b/ui/base.js
index b83752f1..b47fa4b3 100755
--- a/ui/base.js
+++ b/ui/base.js
@@ -981,7 +981,7 @@ function resetToOriginalImage(image){
 
 /********************************************************* Zooming ***/
 
-function fitNImages(n){
+function fitNImages(n, fixed_proportions){
 	var image = getImage()
 	var w = image.outerWidth(true)
 	var h = image.outerHeight(true)
diff --git a/ui/data.js b/ui/data.js
index f51cec87..fb61fc30 100755
--- a/ui/data.js
+++ b/ui/data.js
@@ -996,8 +996,10 @@ function loadSettings(){
 
 	if(toggleSingleImageMode('?') == 'on'){
 		var w = SETTINGS['screen-images-single-image-mode']
-		var p = SETTINGS['single-image-mode-proportions']
-		toggleImageProportions(p)
+		if(window.PROPORTIONS_RATIO_THRESHOLD == null){
+			var p = SETTINGS['single-image-mode-proportions']
+			toggleImageProportions(p)
+		}
 	} else {
 		var w = SETTINGS['screen-images-ribbon-mode']
 		toggleImageInfo(SETTINGS['image-info-ribbon-mode'] == 'on' ? 'on' : 'off')
diff --git a/ui/keybindings.js b/ui/keybindings.js
index 395d4754..35d69917 100755
--- a/ui/keybindings.js
+++ b/ui/keybindings.js
@@ -130,12 +130,14 @@ var KEYBOARD_CONFIG = {
 		title: 'Single image mode',
 		doc: 'To toggle between this and ribbon modes press <b>Enter</b>.',
 
+		/*
 		F: doc('Toggle view proportions', 
 			function(){ 
 				var mode = toggleImageProportions() 
 				showStatus('Fitting image to:', mode + '...')
 				centerRibbons()
 			}),
+		*/
 		Esc: doc('Exit single image mode', 
 				function(){ 
 					toggleSingleImageMode('off') 
@@ -226,6 +228,18 @@ var KEYBOARD_CONFIG = {
 						return false
 					}),
 			},
+
+		// zooming...
+		'#1': doc('Fit one image', function(){ fitNImages(1) }),
+		'#2': doc('Fit two images', function(){ fitNImages(2) }),
+		'#3': doc('Fit three images', function(){ fitNImages(3) }),
+		'#4': doc('Fit four images', function(){ fitNImages(4) }),
+		'#5': doc('Fit five images', function(){ fitNImages(5) }),
+		'#6': doc('Fit six images', function(){ fitNImages(6) }),
+		'#7': doc('Fit seven images', function(){ fitNImages(7) }),
+		'#8': doc('Fit eight images', function(){ fitNImages(8) }),
+		'#9': doc('Fit nine images', function(){ fitNImages(9) }),
+
 	},
 
 
@@ -410,16 +424,6 @@ var KEYBOARD_CONFIG = {
 
 
 		// zooming...
-		'#1': doc('Fit one image', function(){ fitNImages(1) }),
-		'#2': doc('Fit two images', function(){ fitNImages(2) }),
-		'#3': doc('Fit three images', function(){ fitNImages(3) }),
-		'#4': doc('Fit four images', function(){ fitNImages(4) }),
-		'#5': doc('Fit five images', function(){ fitNImages(5) }),
-		'#6': doc('Fit six images', function(){ fitNImages(6) }),
-		'#7': doc('Fit seven images', function(){ fitNImages(7) }),
-		'#8': doc('Fit eight images', function(){ fitNImages(8) }),
-		'#9': doc('Fit nine images', function(){ fitNImages(9) }),
-
 		'-': doc('Zoom in', function(){ zoomOut() }),
 		'=': doc('Zoom out', function(){ zoomIn() }),
 
diff --git a/ui/setup.js b/ui/setup.js
index 89001324..9cd9ca5b 100755
--- a/ui/setup.js
+++ b/ui/setup.js
@@ -3,6 +3,13 @@
 *
 **********************************************************************/
 
+// A threshold after which the image block ratio will be changed to 
+// 'fit-viewer' in single image mode...
+//
+// NOTE: if null this feature will be disabled.
+var PROPORTIONS_RATIO_THRESHOLD = 1.5
+
+
 
 /**********************************************************************
 * Setup
@@ -160,6 +167,25 @@ function setupDataBindings(viewer){
 				SETTINGS['screen-images-ribbon-mode'] = n
 			}
 
+			// update proportions...
+			if(window.PROPORTIONS_RATIO_THRESHOLD != null 
+					&& toggleSingleImageMode('?') == 'on'){
+				var viewer = $('.viewer')
+				//var w = getVisibleImageSize('width')
+				var h = getVisibleImageSize('height')
+				//var W = viewer.innerWidth()
+				var H = viewer.innerHeight()
+
+				//var m = Math.min(W/w, H/h)
+				var m = H/h
+
+				if(m < PROPORTIONS_RATIO_THRESHOLD){
+					toggleImageProportions('fit-viewer')
+				} else {
+					toggleImageProportions('none')
+				}
+			}
+
 			// update previews...
 			updateImages()
 		})