diff --git a/kadai1/convert/conver.go b/kadai1/convert/conver.go
new file mode 100644
index 00000000..943470c4
--- /dev/null
+++ b/kadai1/convert/conver.go
@@ -0,0 +1,75 @@
+package convert
+
+import (
+	"fmt"
+	"image"
+	"image/gif"
+	_ "image/jpeg"
+	"image/png"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+)
+
+//再帰的にファイルを読み込む
+func GetAllFile(pathname string, ipt []string) ([]string, error) {
+	rd, err := ioutil.ReadDir(pathname)
+	if err != nil {
+		fmt.Println("Failed to read dir:", err)
+		return ipt, err
+	}
+	for _, fi := range rd {
+		if fi.IsDir() {
+			fullDir := pathname + "/" + fi.Name()
+			ipt, err = GetAllFile(fullDir, ipt)
+			if err != nil {
+				fmt.Println("Failed to read dir:", err)
+				return ipt, err
+			}
+		} else {
+			fullName := pathname + "/" + fi.Name()
+			ipt = append(ipt, fullName)
+		}
+	}
+	return ipt, nil
+}
+
+//画像の形式を変換する
+func Conv(ipt, opt string) (s string, err error) {
+	s1 := "right"
+	file, err := os.Open(ipt)
+	if err != nil {
+		return s1, err
+	}
+	//assert(err, "Invalid image file path ")
+	defer file.Close()
+
+	img, _, err := image.Decode(file)
+	if err != nil {
+		return s1, err
+	}
+	//assert(err, "Failed to convert file to image.")
+
+	out, err := os.Create(opt)
+	if err != nil {
+		return s1, err
+	}
+	defer out.Close()
+
+	switch filepath.Ext(opt) {
+	case ".png":
+		err = png.Encode(out, img)
+	case ".gif":
+		err = gif.Encode(out, img, nil)
+	}
+	if err != nil {
+		return s1, err
+	}
+	return s1, nil
+}
+
+//func assert(err error, msg string) {
+//	if err != nil {
+//		panic(err.Error() + ":" + msg)
+//	}
+//}
diff --git a/kadai1/convert/conver_test.go b/kadai1/convert/conver_test.go
new file mode 100644
index 00000000..c3dc11f4
--- /dev/null
+++ b/kadai1/convert/conver_test.go
@@ -0,0 +1,47 @@
+package convert
+
+import (
+	"convert"
+	"path/filepath"
+	"testing"
+)
+
+func TestAllfile(t *testing.T) {
+	t.Helper()
+	var s []string
+	output, _ := GetAllFile("./img", s)
+	if len(output) != 15 {
+		t.Errorf("Image file does not complete readed,expected 15,but %v ", len(output)) //画像の枚数が違う
+	}
+}
+
+func TestTableAllfile(t *testing.T) {
+	t.Helper()
+	var s []string
+	var tests = []struct {
+		pathinput string
+		expect    int
+	}{
+		{"./img/img_test1", 3},
+		{"./img/img_test2", 4},
+		{"./img/img_test3", 5},
+	}
+	for _, te := range tests {
+		output, _ := GetAllFile(te.pathinput, s)
+		if len(output) != te.expect {
+			t.Errorf("Image file does not complete readed,expected %v,but %v ", tests[1], len(output)) //画像の枚数が違う
+		}
+	}
+}
+
+func TestConv(t *testing.T) {
+	t.Helper()
+	err := convert.Conv("./img/1.0.jpg", "./img/1.0.png")
+	if err != nil {
+		t.Errorf("error happened %v", err)
+	}
+	matches, _ := filepath.Glob("./img/*.png")
+	if matches == nil {
+		t.Errorf("Image file does not converted %v", matches)
+	}
+}
diff --git a/kadai1/convert/img/1.0.jpg b/kadai1/convert/img/1.0.jpg
new file mode 100644
index 00000000..b168a75b
Binary files /dev/null and b/kadai1/convert/img/1.0.jpg differ
diff --git a/kadai1/convert/img/1.1.jpg b/kadai1/convert/img/1.1.jpg
new file mode 100644
index 00000000..b168a75b
Binary files /dev/null and b/kadai1/convert/img/1.1.jpg differ
diff --git a/kadai1/convert/img/1.2.jpg b/kadai1/convert/img/1.2.jpg
new file mode 100644
index 00000000..b168a75b
Binary files /dev/null and b/kadai1/convert/img/1.2.jpg differ
diff --git a/kadai1/convert/img/img_test1/1.jpg b/kadai1/convert/img/img_test1/1.jpg
new file mode 100644
index 00000000..b168a75b
Binary files /dev/null and b/kadai1/convert/img/img_test1/1.jpg differ
diff --git a/kadai1/convert/img/img_test1/2.jpg b/kadai1/convert/img/img_test1/2.jpg
new file mode 100644
index 00000000..b168a75b
Binary files /dev/null and b/kadai1/convert/img/img_test1/2.jpg differ
diff --git a/kadai1/convert/img/img_test1/3.jpg b/kadai1/convert/img/img_test1/3.jpg
new file mode 100644
index 00000000..b168a75b
Binary files /dev/null and b/kadai1/convert/img/img_test1/3.jpg differ
diff --git a/kadai1/convert/img/img_test2/1.jpg b/kadai1/convert/img/img_test2/1.jpg
new file mode 100644
index 00000000..b168a75b
Binary files /dev/null and b/kadai1/convert/img/img_test2/1.jpg differ
diff --git a/kadai1/convert/img/img_test2/2.jpg b/kadai1/convert/img/img_test2/2.jpg
new file mode 100644
index 00000000..b168a75b
Binary files /dev/null and b/kadai1/convert/img/img_test2/2.jpg differ
diff --git a/kadai1/convert/img/img_test2/3.jpg b/kadai1/convert/img/img_test2/3.jpg
new file mode 100644
index 00000000..b168a75b
Binary files /dev/null and b/kadai1/convert/img/img_test2/3.jpg differ
diff --git a/kadai1/convert/img/img_test2/4.jpg b/kadai1/convert/img/img_test2/4.jpg
new file mode 100644
index 00000000..b168a75b
Binary files /dev/null and b/kadai1/convert/img/img_test2/4.jpg differ
diff --git a/kadai1/convert/img/img_test3/1.jpg b/kadai1/convert/img/img_test3/1.jpg
new file mode 100644
index 00000000..b168a75b
Binary files /dev/null and b/kadai1/convert/img/img_test3/1.jpg differ
diff --git a/kadai1/convert/img/img_test3/2.jpg b/kadai1/convert/img/img_test3/2.jpg
new file mode 100644
index 00000000..b168a75b
Binary files /dev/null and b/kadai1/convert/img/img_test3/2.jpg differ
diff --git a/kadai1/convert/img/img_test3/3.jpg b/kadai1/convert/img/img_test3/3.jpg
new file mode 100644
index 00000000..b168a75b
Binary files /dev/null and b/kadai1/convert/img/img_test3/3.jpg differ
diff --git a/kadai1/convert/img/img_test3/4.jpg b/kadai1/convert/img/img_test3/4.jpg
new file mode 100644
index 00000000..b168a75b
Binary files /dev/null and b/kadai1/convert/img/img_test3/4.jpg differ
diff --git a/kadai1/convert/img/img_test3/5.jpg b/kadai1/convert/img/img_test3/5.jpg
new file mode 100644
index 00000000..b168a75b
Binary files /dev/null and b/kadai1/convert/img/img_test3/5.jpg differ
diff --git a/kadai1/go.mod b/kadai1/go.mod
new file mode 100644
index 00000000..ea118c73
--- /dev/null
+++ b/kadai1/go.mod
@@ -0,0 +1,3 @@
+module image.go
+
+go 1.16
diff --git a/kadai1/img/1.0.jpg b/kadai1/img/1.0.jpg
new file mode 100644
index 00000000..b168a75b
Binary files /dev/null and b/kadai1/img/1.0.jpg differ
diff --git a/kadai1/img/1.1.jpg b/kadai1/img/1.1.jpg
new file mode 100644
index 00000000..b168a75b
Binary files /dev/null and b/kadai1/img/1.1.jpg differ
diff --git a/kadai1/img/1.2.jpg b/kadai1/img/1.2.jpg
new file mode 100644
index 00000000..b168a75b
Binary files /dev/null and b/kadai1/img/1.2.jpg differ
diff --git a/kadai1/img/img_test/1.jpg b/kadai1/img/img_test/1.jpg
new file mode 100644
index 00000000..b168a75b
Binary files /dev/null and b/kadai1/img/img_test/1.jpg differ
diff --git a/kadai1/img/img_test/2.jpg b/kadai1/img/img_test/2.jpg
new file mode 100644
index 00000000..b168a75b
Binary files /dev/null and b/kadai1/img/img_test/2.jpg differ
diff --git a/kadai1/img/img_test/3.jpg b/kadai1/img/img_test/3.jpg
new file mode 100644
index 00000000..b168a75b
Binary files /dev/null and b/kadai1/img/img_test/3.jpg differ
diff --git a/kadai1/main.go b/kadai1/main.go
new file mode 100644
index 00000000..9219dbb9
--- /dev/null
+++ b/kadai1/main.go
@@ -0,0 +1,39 @@
+/*This is a training code for learning Go language.
+And this code can change the format of images as you like*/
+package main
+
+import (
+	"bufio"
+	"convert"
+	"fmt"
+	"os"
+	"strings"
+)
+
+type oriPath struct {
+	inputPA  string
+	outputPA string
+}
+
+func main() {
+	var a oriPath
+	a.inputPA = "./img"
+	a.outputPA = "./img"
+	scanner := bufio.NewScanner(os.Stdin)
+	fmt.Print("Input the image format you want(like png or gif):")
+	if !scanner.Scan() {
+		fmt.Println("Please input the format.")
+		return
+	}
+	srcPath := scanner.Text()
+
+	var s []string
+	s, _ = convert.GetAllFile(a.inputPA, s)
+	for _, i := range s {
+		j := strings.Replace(i, "jpg", srcPath, -1) //jpgから任意の形式へ変換する
+		err := convert.Conv(i, j)
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "%s\n", err.Error())
+		}
+	}
+}