diff --git a/PhotoWalker/README.md b/PhotoWalker/README.md
new file mode 100644
index 0000000..6c7e063
--- /dev/null
+++ b/PhotoWalker/README.md
@@ -0,0 +1,37 @@
+# Photo Walker
+
+A simple photo(file) walker written in go.
+
+## Usage
+
+First download
+
+```shell
+$ go get -u github.com/iochen/GoSimpleProjects/tree/master/PhotoWalker
+```
+
+or download `main.go`
+
+```shell
+$ go run main.go
+```
+
+
+
+```
+Usage of PhotoWalker:
+  -d string
+        The directory you want to walk. (default "./")
+  -e string
+        The extension(s) you want to match. (default "jpg,jpeg,png,raw")
+  -o string
+        The directory you want to output. (default "./output/")
+  -r    If you want to remove same file in output directory.
+```
+
+
+
+## LICENSE
+
+**MIT LICENSE**
+
diff --git a/PhotoWalker/main.go b/PhotoWalker/main.go
new file mode 100644
index 0000000..058dfa5
--- /dev/null
+++ b/PhotoWalker/main.go
@@ -0,0 +1,107 @@
+package main
+
+import (
+	"crypto/sha1"
+	"flag"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"log"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+const sep = string(filepath.Separator)
+
+func main() {
+	walkDir := flag.String("d", "."+sep, "The directory you want to walk.")
+	outDir := flag.String("o", "."+sep+"output"+sep, "The directory you want to output.")
+	ext := flag.String("e", "jpg,jpeg,png,raw", "The extension(s) you want to match.")
+	rmSame := flag.Bool("r", false, "If you want to remove same file in output directory.")
+	flag.Parse()
+
+	if (*outDir)[len(*outDir)-1] != filepath.Separator {
+		*outDir += sep
+	}
+
+	extExist := ExtSet(*ext)
+	WalkDir(*walkDir, *outDir, extExist)
+	if *rmSame {
+		RemoveSameFile(*outDir)
+	}
+}
+
+func ExtSet(ext string) map[string]bool {
+	extExist := make(map[string]bool)
+	extList := strings.Split(ext, ",")
+	for _, ext := range extList {
+		extExist["."+ext] = true
+	}
+	return extExist
+}
+
+func WalkDir(walkDir, outDir string, extExist map[string]bool) {
+	var pathList []string
+	err := filepath.Walk(walkDir, func(path string, info os.FileInfo, err error) error {
+		if err != nil {
+			return err
+		}
+		ext := filepath.Ext(path)
+		if !info.IsDir() && extExist[ext] {
+			pathList = append(pathList, path)
+		}
+		return nil
+	})
+	checkErr(err)
+	CopyFile(pathList, outDir)
+}
+
+func CopyFile(pathList []string, outDir string) {
+	if len(pathList) == 0 {
+		return
+	}
+	if _, err := os.Stat(outDir); os.IsNotExist(err) {
+		err = os.MkdirAll(outDir, 0755)
+		checkErr(err)
+	}
+	for _, path := range pathList {
+		fileName := filepath.Base(path)
+		bytes, err := ioutil.ReadFile(path)
+		checkErr(err)
+		err = ioutil.WriteFile(outDir+fileName, bytes, 0644)
+		checkErr(err)
+	}
+}
+
+func RemoveSameFile(workDir string) {
+	SHA1List := make(map[string]bool)
+	makeSHA1 := func(bytes *[]byte) string {
+		h := sha1.New()
+		_, err := io.WriteString(h, string(*bytes))
+		checkErr(err)
+		return fmt.Sprintf("%x", h.Sum(nil))
+	}
+	err := filepath.Walk(workDir, func(path string, info os.FileInfo, err error) error {
+		if err != nil {
+			return err
+		}
+		bytes, err := ioutil.ReadFile(path)
+		checkErr(err)
+		hash := makeSHA1(&bytes)
+		if SHA1List[hash] {
+			err := os.Remove(path)
+			checkErr(err)
+		} else {
+			SHA1List[hash] = true
+		}
+		return nil
+	})
+	checkErr(err)
+}
+
+func checkErr(err error) {
+	if err != nil {
+		log.Println(err)
+	}
+}
diff --git a/SimpleDownloader/README.md b/SimpleDownloader/README.md
index cd68996..50d1d3d 100644
--- a/SimpleDownloader/README.md
+++ b/SimpleDownloader/README.md
@@ -10,7 +10,7 @@ A simple downloader written in go.
 
 Use command:
 ```bash
-$ go get -u iochen.com/simpledownloader
+$ go get -u github.com/iochen/GoSimpleProjects/tree/master/SimpleDownloader
 ```
 (or download from [releases](https://github.com/iochen/SimpleDownloader/releases))