diff --git a/modules/setting/common_mime.go b/modules/setting/common_mime.go
new file mode 100644
index 0000000000000..99602bc784907
--- /dev/null
+++ b/modules/setting/common_mime.go
@@ -0,0 +1,92 @@
+// Copyright 2020 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package setting
+
+import (
+	"strings"
+)
+
+// https://s-randomfiles.s3.amazonaws.com/mime/allMimeTypes.txt
+
+var commonMimeTypes = []struct {
+	names []string
+	types []string
+}{
+	{[]string{
+		"zipped",
+		"zip",
+		"compressed",
+		"packed",
+	}, []string{
+		"application/zip",
+		"application/x-zip-compressed",
+		"multipart/x-zip",
+		"application/gzip",
+		"application/x-gzip",
+		"application/x-gzip-compressed",
+		"multipart/gzip",
+		"application/x-compressed-tar",
+		"application/x-gtar",
+		"application/x-tgz",
+		"application/rar",
+		"application/x-rar-compressed",
+		"application/x-7z-compressed",
+		"application/x-compress",
+	}},
+	{[]string{
+		"image",
+		"picture",
+	}, []string{
+		"image/jpeg",
+		"image/png",
+		"image/apng",
+		"image/bmp",
+		"image/gif",
+	}},
+	{[]string{
+		"txt",
+		"text",
+	}, []string{
+		"text/plain",
+	}},
+	{[]string{
+		"pdf",
+	}, []string{
+		"application/pdf",
+	}},
+}
+
+func expandCommonMimeTypesString(typeList string) string {
+	return strings.Join(expandCommonMimeTypes(strings.Split(typeList, ",")), ",")
+}
+
+func expandCommonMimeTypes(types []string) []string {
+	list := make([]string, 0, len(types))
+individuals:
+	for _, name := range types {
+		if !strings.Contains(name, "/") {
+			normalized := strings.TrimSpace(strings.ToLower(name))
+			for _, candidate := range commonMimeTypes {
+				if isStringInSlice(normalized, candidate.names) {
+					list = append(list, candidate.types...)
+					continue individuals
+				}
+			}
+		} else {
+			list = append(list, name)
+		}
+	}
+	return list
+}
+
+// Can't import 'util' because it's a circular reference
+func isStringInSlice(target string, slice []string) bool {
+	for i := 0; i < len(slice); i++ {
+		if slice[i] == target {
+			return true
+		}
+	}
+	return false
+}
diff --git a/modules/setting/repository.go b/modules/setting/repository.go
index 8af3eaaf46933..89951921170ef 100644
--- a/modules/setting/repository.go
+++ b/modules/setting/repository.go
@@ -222,6 +222,8 @@ func newRepository() {
 		log.Fatal("Failed to map Repository.PullRequest settings: %v", err)
 	}
 
+	Repository.Upload.AllowedTypes = expandCommonMimeTypes(Repository.Upload.AllowedTypes)
+
 	if !filepath.IsAbs(Repository.Upload.TempPath) {
 		Repository.Upload.TempPath = path.Join(AppWorkPath, Repository.Upload.TempPath)
 	}
diff --git a/modules/setting/setting.go b/modules/setting/setting.go
index 714015c47589d..a7f7d96a8e4e7 100644
--- a/modules/setting/setting.go
+++ b/modules/setting/setting.go
@@ -827,7 +827,7 @@ func NewContext() {
 	if !filepath.IsAbs(AttachmentPath) {
 		AttachmentPath = path.Join(AppWorkPath, AttachmentPath)
 	}
-	AttachmentAllowedTypes = strings.Replace(sec.Key("ALLOWED_TYPES").MustString("image/jpeg,image/png,application/zip,application/gzip"), "|", ",", -1)
+	AttachmentAllowedTypes = expandCommonMimeTypesString(strings.Replace(sec.Key("ALLOWED_TYPES").MustString("image/jpeg,image/png,application/zip,application/gzip"), "|", ",", -1))
 	AttachmentMaxSize = sec.Key("MAX_SIZE").MustInt64(4)
 	AttachmentMaxFiles = sec.Key("MAX_FILES").MustInt(5)
 	AttachmentEnabled = sec.Key("ENABLED").MustBool(true)