diff --git a/data.go b/data.go
index d912864..382be17 100644
--- a/data.go
+++ b/data.go
@@ -31,6 +31,7 @@ const (
 	optQualityPrefix   = "q"
 	optSignaturePrefix = "s"
 	optSizeDelimiter   = "x"
+	optScaleUp         = "scaleUp"
 )
 
 // URLError reports a malformed URL error.
@@ -66,7 +67,8 @@ type Options struct {
 	// HMAC Signature for signed requests.
 	Signature string
 
-	// Allow images to scale beyond their original dimensions.
+	// Allow image to scale beyond its original dimensions.  This value
+	// will always be overwritten by the value of Proxy.ScaleUp.
 	ScaleUp bool
 }
 
@@ -93,6 +95,9 @@ func (o Options) String() string {
 	if o.Signature != "" {
 		fmt.Fprintf(buf, ",%s%s", string(optSignaturePrefix), o.Signature)
 	}
+	if o.ScaleUp {
+		fmt.Fprintf(buf, ",%s", optScaleUp)
+	}
 	return buf.String()
 }
 
@@ -166,6 +171,8 @@ func ParseOptions(str string) Options {
 			options.FlipVertical = true
 		case opt == optFlipHorizontal:
 			options.FlipHorizontal = true
+		case opt == optScaleUp: // this option is intentionally not documented above
+			options.ScaleUp = true
 		case strings.HasPrefix(opt, optRotatePrefix):
 			value := strings.TrimPrefix(opt, optRotatePrefix)
 			options.Rotate, _ = strconv.Atoi(value)
diff --git a/imageproxy.go b/imageproxy.go
index 8be6ce8..c8b5342 100644
--- a/imageproxy.go
+++ b/imageproxy.go
@@ -81,7 +81,7 @@ func NewProxy(transport http.RoundTripper, cache Cache) *Proxy {
 
 	client := new(http.Client)
 	client.Transport = &httpcache.Transport{
-		Transport:           &TransformingTransport{transport, client, &proxy},
+		Transport:           &TransformingTransport{transport, client},
 		Cache:               cache,
 		MarkCachedResponses: true,
 	}
@@ -105,6 +105,9 @@ func (p *Proxy) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	// assign static settings from proxy to req.Options
+	req.Options.ScaleUp = p.ScaleUp
+
 	if !p.allowed(req) {
 		msg := fmt.Sprintf("request does not contain an allowed host or valid signature")
 		glog.Error(msg)
@@ -259,9 +262,6 @@ type TransformingTransport struct {
 	// used rather than Transport directly in order to ensure that
 	// responses are properly cached.
 	CachingClient *http.Client
-
-	// Proxy is used to access command line flag settings during roundtripping.
-	Proxy *Proxy
 }
 
 // RoundTrip implements the http.RoundTripper interface.
@@ -287,11 +287,6 @@ func (t *TransformingTransport) RoundTrip(req *http.Request) (*http.Response, er
 
 	opt := ParseOptions(req.URL.Fragment)
 
-	// assign static settings from proxy to options
-	if t.Proxy != nil {
-		opt.ScaleUp = t.Proxy.ScaleUp
-	}
-
 	img, err := Transform(b, opt)
 	if err != nil {
 		glog.Errorf("error transforming image: %v", err)
diff --git a/imageproxy_test.go b/imageproxy_test.go
index 298e41f..9ddee1d 100644
--- a/imageproxy_test.go
+++ b/imageproxy_test.go
@@ -12,8 +12,6 @@ import (
 	"net/url"
 	"strings"
 	"testing"
-
-	"github.com/gregjones/httpcache"
 )
 
 func TestAllowed(t *testing.T) {
@@ -206,15 +204,6 @@ func TestCheck304(t *testing.T) {
 	}
 }
 
-// make sure that the proxy is passed to transport in order
-// to access the command line flags.
-func TestProxyPointer(t *testing.T) {
-	p := NewProxy(nil, nil)
-	if p.Client.Transport.(*httpcache.Transport).Transport.(*TransformingTransport).Proxy != p {
-		t.Errorf("Transport doesnt have proxy pointer")
-	}
-}
-
 // testTransport is an http.RoundTripper that returns certained canned
 // responses for particular requests.
 type testTransport struct{}