diff --git a/include/KeyFrame.h b/include/KeyFrame.h
index 5a5565a0..8a3fcfd5 100644
--- a/include/KeyFrame.h
+++ b/include/KeyFrame.h
@@ -141,6 +141,9 @@ namespace openshot {
 		/// Get current point (or closest point) from the X coordinate (i.e. the frame number)
 		Point GetClosestPoint(Point p);
 
+		/// Get max point (by Y coordinate)
+		Point GetMaxPoint();
+
 		// Get the number of values (i.e. coordinates on the X axis)
 		long int GetLength();
 
diff --git a/src/Clip.cpp b/src/Clip.cpp
index a93db20a..2ce820e9 100644
--- a/src/Clip.cpp
+++ b/src/Clip.cpp
@@ -597,13 +597,32 @@ tr1::shared_ptr<Frame> Clip::GetOrCreateFrame(long int number)
 		// Debug output
 		ZmqLogger::Instance()->AppendDebugMethod("Clip::GetOrCreateFrame (from reader)", "number", number, "samples_in_frame", samples_in_frame, "", -1, "", -1, "", -1, "", -1);
 
-		// Set max image size (used for performance optimization)
-		if (scale_x.GetValue(number) > 1.000001 || scale_y.GetValue(number) > 1.000001)
-			// Scaling larger, use original image size (slower but better quality)
+		// Determine the max size of this clips source image (based on the timeline's size, the scaling mode,
+		// and the scaling keyframes). This is a performance improvement, to keep the images as small as possible,
+		// without loosing quality.
+		if (scale == SCALE_FIT || scale == SCALE_STRETCH) {
+			// Best fit or Stretch scaling (based on max timeline size * scaling keyframes)
+			float max_scale_x = scale_x.GetMaxPoint().co.Y;
+			float max_scale_y = scale_y.GetMaxPoint().co.Y;
+			reader->SetMaxSize(max_width * max_scale_x, max_height * max_scale_y);
+
+		} else if (scale == SCALE_CROP) {
+			// Cropping scale mode (based on max timeline size * cropped size * scaling keyframes)
+			float max_scale_x = scale_x.GetMaxPoint().co.Y;
+			float max_scale_y = scale_y.GetMaxPoint().co.Y;
+			QSize width_size(max_width * max_scale_x, round(max_width / (float(reader->info.width) / float(reader->info.height))));
+			QSize height_size(round(max_height / (float(reader->info.height) / float(reader->info.width))), max_height * max_scale_y);
+
+			// respect aspect ratio
+			if (width_size.width() >= max_width && width_size.height() >= max_height)
+				reader->SetMaxSize(width_size.width(), width_size.height());
+			else
+				reader->SetMaxSize(height_size.width(), height_size.height());
+
+		} else {
+			// No scaling, use original image size (slower)
 			reader->SetMaxSize(0, 0);
-		else
-			// No scaling applied, use max_size (usually the size of the timeline)
-			reader->SetMaxSize(max_width, max_height);
+		}
 
 		// Attempt to get a frame (but this could fail if a reader has just been closed)
 		new_frame = reader->GetFrame(number);
diff --git a/src/KeyFrame.cpp b/src/KeyFrame.cpp
index 6c3777df..4bb4b062 100644
--- a/src/KeyFrame.cpp
+++ b/src/KeyFrame.cpp
@@ -220,6 +220,25 @@ Point Keyframe::GetClosestPoint(Point p) {
 	return closest;
 }
 
+// Get max point (by Y coordinate)
+Point Keyframe::GetMaxPoint() {
+	Point maxPoint(-1, -1);
+
+	// loop through points, and find the largest Y value
+	for (long int x = 0; x < Points.size(); x++) {
+		// Get each point
+		Point existing_point = Points[x];
+
+		// Is point larger than max point
+		if (existing_point.co.Y >= maxPoint.co.Y) {
+			// New max point found
+			maxPoint = existing_point;
+		}
+	}
+
+	return maxPoint;
+}
+
 // Get the value at a specific index
 float Keyframe::GetValue(long int index)
 {
diff --git a/src/QtImageReader.cpp b/src/QtImageReader.cpp
index 5bfecc59..8ee56374 100644
--- a/src/QtImageReader.cpp
+++ b/src/QtImageReader.cpp
@@ -123,6 +123,11 @@ tr1::shared_ptr<Frame> QtImageReader::GetFrame(long int requested_frame) throw(R
 	// A max_width/max_height = 0 means do not scale (probably because we are scaling the image larger than 100%)
 	if (max_width != 0 && max_height != 0 && max_width < info.width && max_height < info.height)
 	{
+		// Remove cache that is no longer valid (if needed)
+		if (cached_image && !(cached_image->width() == max_width || cached_image->height() == max_height))
+			// Expire this cache
+			cached_image.reset();
+
 		// Scale image smaller (or use a previous scaled image)
 		if (!cached_image) {
 			// Create a scoped lock, allowing only a single thread to run the following code at one time
diff --git a/tests/KeyFrame_Tests.cpp b/tests/KeyFrame_Tests.cpp
index 4d970465..0a8739c2 100644
--- a/tests/KeyFrame_Tests.cpp
+++ b/tests/KeyFrame_Tests.cpp
@@ -244,6 +244,32 @@ TEST(Keyframe_Get_Closest_Point)
 
 }
 
+
+TEST(Keyframe_Get_Max_Point)
+{
+	// Create a keyframe curve
+	Keyframe kf;
+	kf.AddPoint(1, 1.0);
+
+	// Spot check values from the curve
+	CHECK_EQUAL(kf.GetMaxPoint().co.Y, 1.0);
+
+	kf.AddPoint(2, 0.0);
+
+	// Spot check values from the curve
+	CHECK_EQUAL(kf.GetMaxPoint().co.Y, 1.0);
+
+	kf.AddPoint(3, 2.0);
+
+	// Spot check values from the curve
+	CHECK_EQUAL(kf.GetMaxPoint().co.Y, 2.0);
+
+	kf.AddPoint(4, 1.0);
+
+	// Spot check values from the curve
+	CHECK_EQUAL(kf.GetMaxPoint().co.Y, 2.0);
+}
+
 TEST(Keyframe_Scale_Keyframe)
 {
 	// Create a keyframe curve with 2 points