diff --git a/README.md b/README.md
index 856f5a9..1f1b676 100644
--- a/README.md
+++ b/README.md
@@ -4,7 +4,7 @@ imageproxy is a caching image proxy server written in go.  It features:
 
  - basic image adjustments like resizing, cropping, and rotation
  - access control using host whitelists or request signing (HMAC-SHA256)
- - support for jpeg, png, webp (decode only), and gif image formats (including animated gifs)
+ - support for jpeg, png, webp & tiff (decode only), and gif image formats (including animated gifs)
  - on-disk caching, respecting the cache headers of the original images
  - easy deployment, since it's pure go
 
diff --git a/imageproxy.go b/imageproxy.go
index 4fb65b5..b06329b 100644
--- a/imageproxy.go
+++ b/imageproxy.go
@@ -323,7 +323,7 @@ func (t *TransformingTransport) RoundTrip(req *http.Request) (*http.Response, er
 	resp.Header.WriteSubset(buf, map[string]bool{
 		"Content-Length": true,
 		// exclude Content-Type header if the format may have changed during transformation
-		"Content-Type": opt.Format != "" || resp.Header.Get("Content-Type") == "image/webp",
+		"Content-Type": opt.Format != "" || resp.Header.Get("Content-Type") == "image/webp" || resp.Header.Get("Content-Type") == "image/tiff",
 	})
 	fmt.Fprintf(buf, "Content-Length: %d\n\n", len(img))
 	buf.Write(img)
diff --git a/transform.go b/transform.go
index 0b5b993..1e00063 100644
--- a/transform.go
+++ b/transform.go
@@ -25,6 +25,7 @@ import (
 
 	"github.com/disintegration/imaging"
 	_ "golang.org/x/image/webp" // register webp format
+	_ "golang.org/x/image/tiff" // register tiff format
 	"willnorris.com/go/gifresize"
 )
 
@@ -64,7 +65,7 @@ func Transform(img []byte, opt Options) ([]byte, error) {
 		if err != nil {
 			return nil, err
 		}
-	case "jpeg", "webp": // default to encoding webp as jpeg
+	case "jpeg", "webp", "tiff": // default to encoding webp & tiff as jpeg
 		quality := opt.Quality
 		if quality == 0 {
 			quality = defaultQuality