YAMLType,
        TOMLType,
        PNGType,
+       GIFType,
+       BMPType,
        JPEGType,
        WEBPType,
        AVIType,
 
 func init() {
        sort.Sort(DefaultTypes)
+
+       // Sanity check.
+       seen := make(map[Type]bool)
+       for _, t := range DefaultTypes {
+               if seen[t] {
+                       panic(fmt.Sprintf("MediaType %s duplicated in list", t))
+               }
+               seen[t] = true
+       }
 }
 
 // Types is a slice of media types.
 
 
 import (
        "encoding/json"
+       "fmt"
        "io/ioutil"
        "path/filepath"
        "sort"
 
        }
 
-       c.Assert(len(DefaultTypes), qt.Equals, 31)
+       c.Assert(len(DefaultTypes), qt.Equals, 33)
 }
 
 func TestGetByType(t *testing.T) {
                        content, err := ioutil.ReadFile(filename)
                        c.Assert(err, qt.IsNil)
                        ext := strings.TrimPrefix(paths.Ext(filename), ".")
+                       fmt.Println("=>", ext)
                        expected, _, found := mtypes.GetFirstBySuffix(ext)
                        c.Assert(found, qt.IsTrue)
                        got := FromContent(mtypes, ext, content)