diff --git a/runtime_test.go b/runtime_test.go
index 1190510279..eea69aa5dc 100644
--- a/runtime_test.go
+++ b/runtime_test.go
@@ -17,7 +17,7 @@ import (
 )
 
 const unitTestImageName string = "docker-ut"
-
+const unitTestImageId string = "e9aa60c60128cad1"
 const unitTestStoreBase string = "/var/lib/docker/unit-tests"
 
 func nuke(runtime *Runtime) error {
diff --git a/tags.go b/tags.go
index 140182890d..7133649f6e 100644
--- a/tags.go
+++ b/tags.go
@@ -160,7 +160,7 @@ func (store *TagStore) GetImage(repoName, tagOrId string) (*Image, error) {
 	}
 	//go through all the tags, to see if tag is in fact an ID
 	for _, revision := range repo {
-		if utils.TruncateId(revision) == tagOrId {
+		if strings.HasPrefix(revision, tagOrId) {
 			return store.graph.Get(revision)
 		}
 	}
diff --git a/tags_test.go b/tags_test.go
new file mode 100644
index 0000000000..5d03275909
--- /dev/null
+++ b/tags_test.go
@@ -0,0 +1,49 @@
+package docker
+
+import (
+	"testing"
+)
+
+func TestLookupImage(t *testing.T) {
+	runtime, err := newTestRuntime()
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer nuke(runtime)
+
+	if img, err := runtime.repositories.LookupImage(unitTestImageName); err != nil {
+		t.Fatal(err)
+	} else if img == nil {
+		t.Errorf("Expected 1 image, none found")
+	}
+
+	if img, err := runtime.repositories.LookupImage(unitTestImageName + ":" + DEFAULT_TAG); err != nil {
+		t.Fatal(err)
+	} else if img == nil {
+		t.Errorf("Expected 1 image, none found")
+	}
+
+	if img, err := runtime.repositories.LookupImage(unitTestImageName + ":" + "fail"); err == nil {
+		t.Errorf("Expected error, none found")
+	} else if img != nil {
+		t.Errorf("Expected 0 image, 1 found")
+	}
+
+	if img, err := runtime.repositories.LookupImage("fail:fail"); err == nil {
+		t.Errorf("Expected error, none found")
+	} else if img != nil {
+		t.Errorf("Expected 0 image, 1 found")
+	}
+
+	if img, err := runtime.repositories.LookupImage(unitTestImageId); err != nil {
+		t.Fatal(err)
+	} else if img == nil {
+		t.Errorf("Expected 1 image, none found")
+	}
+
+	if img, err := runtime.repositories.LookupImage(unitTestImageName + ":" + unitTestImageId); err != nil {
+		t.Fatal(err)
+	} else if img == nil {
+		t.Errorf("Expected 1 image, none found")
+	}
+}