diff --git a/photobooth/camera/PictureDimensions.py b/photobooth/camera/PictureDimensions.py
index cce5bde..4b6c6ce 100644
--- a/photobooth/camera/PictureDimensions.py
+++ b/photobooth/camera/PictureDimensions.py
@@ -37,6 +37,8 @@ class PictureDimensions:
 
         self.computeThumbnailDimensions()
 
+        self.computePreviewDimensions(config)
+
     def computeThumbnailDimensions(self):
 
         resize_factor = min((((self.outputSize[i] - (self.numPictures[i] + 1) *
@@ -58,6 +60,17 @@ class PictureDimensions:
                                              pos[j] * self.thumbnailSize[j]
                                              for j in range(2)))
 
+    def computePreviewDimensions(self, config):
+
+        gui_size = (config.getInt('Gui', 'width'),
+                    config.getInt('Gui', 'height'))
+
+        resize_factor = min(min((gui_size[i] / self.captureSize[i]
+                                 for i in range(2))), 1)
+
+        self._preview_size = tuple(int(self.captureSize[i] * resize_factor)
+                                   for i in range(2))
+
     @property
     def numPictures(self):
 
@@ -98,3 +111,8 @@ class PictureDimensions:
     def thumbnailOffset(self):
 
         return self._thumb_offsets
+
+    @property
+    def previewSize(self):
+
+        return self._preview_size
diff --git a/photobooth/camera/__init__.py b/photobooth/camera/__init__.py
index db7c217..1f2c9de 100644
--- a/photobooth/camera/__init__.py
+++ b/photobooth/camera/__init__.py
@@ -121,6 +121,7 @@ class Camera:
         if self._is_preview:
             while self._comm.empty(Workers.CAMERA):
                 picture = ImageOps.mirror(self._cap.getPreview())
+                picture = picture.resize(self._pic_dims.previewSize)
                 self._comm.send(Workers.GUI,
                                 StateMachine.CameraEvent('preview', picture))