diff --git a/kadai2/lfcd85/.gitignore b/kadai2/lfcd85/.gitignore
new file mode 100644
index 0000000..cb29540
--- /dev/null
+++ b/kadai2/lfcd85/.gitignore
@@ -0,0 +1 @@
+bin/convert
diff --git a/kadai2/lfcd85/Makefile b/kadai2/lfcd85/Makefile
new file mode 100644
index 0000000..0ce4479
--- /dev/null
+++ b/kadai2/lfcd85/Makefile
@@ -0,0 +1,12 @@
+bin/convert: cmd/convert/*.go imgconv/*.go
+	GO111MODULE=on go build -o bin/convert cmd/convert/main.go
+
+fmt:
+	go fmt ./...
+	go vet ./...
+
+check:
+	GO111MODULE=on go test ./imgconv/... -v
+
+coverage:
+	GO111MODULE=on go test ./imgconv/... -cover
diff --git a/kadai2/lfcd85/README.md b/kadai2/lfcd85/README.md
new file mode 100644
index 0000000..fe9718c
--- /dev/null
+++ b/kadai2/lfcd85/README.md
@@ -0,0 +1,29 @@
+# imgconv
+
+An implementation for the image conversion command, kadai-1 of Gopherdojo #5.
+
+Gopher道場 #5 課題1 `画像変換コマンド` の実装です。
+
+## Installation
+
+```bash
+$ make bin/convert
+```
+
+## Usage
+
+Specify the target directory as an argument. The given directory is recursively processed. Converted files are outputted under `./output/` directory.
+
+コマンド引数に対象ディレクトリを指定してください。ディレクトリ以下は再帰的に処理されます。変換後のファイルは `./output/` ディレクトリ以下に出力されます。
+
+```bash
+$ bin/convert test/
+```
+
+Input and output image formats can be set by `-f` (from) and `-t` (to) options. Default formats are from JPEG to PNG. JPEG, PNG, GIF are available.
+
+画像形式は `-f` オプション（変換前）・ `-t` オプション（変換後）で指定できます。デフォルトは JPEG → PNG です。JPEG, PNG, GIF 形式が利用可能です。
+
+```bash
+$ bin/convert -f png -t jpeg test/
+```
diff --git a/kadai2/lfcd85/bin/.gitkeep b/kadai2/lfcd85/bin/.gitkeep
new file mode 100644
index 0000000..e69de29
diff --git a/kadai2/lfcd85/cmd/convert/main.go b/kadai2/lfcd85/cmd/convert/main.go
new file mode 100644
index 0000000..e96f994
--- /dev/null
+++ b/kadai2/lfcd85/cmd/convert/main.go
@@ -0,0 +1,22 @@
+// Command bin/convert ...
+package main
+
+import (
+	"flag"
+	"fmt"
+
+	"github.com/gopherdojo/dojo5/kadai2/lfcd85/imgconv"
+)
+
+func main() {
+	from := flag.String("f", "jpeg", "Image format before conversion (default: jpeg)")
+	to := flag.String("t", "png", "Image format after conversion (default: png)")
+	flag.Parse()
+	dirName := flag.Arg(0)
+
+	err := imgconv.Convert(dirName, *from, *to)
+	if err != nil {
+		fmt.Println("error:", err)
+		return
+	}
+}
diff --git a/kadai2/lfcd85/go.mod b/kadai2/lfcd85/go.mod
new file mode 100644
index 0000000..58fa07c
--- /dev/null
+++ b/kadai2/lfcd85/go.mod
@@ -0,0 +1,3 @@
+module github.com/gopherdojo/dojo5/kadai2/lfcd85
+
+go 1.12
diff --git a/kadai2/lfcd85/imgconv/imgconv.go b/kadai2/lfcd85/imgconv/imgconv.go
new file mode 100644
index 0000000..8b2a6eb
--- /dev/null
+++ b/kadai2/lfcd85/imgconv/imgconv.go
@@ -0,0 +1,182 @@
+// Package imgconv provides a recursive conversion of images in the directory.
+package imgconv
+
+import (
+	"errors"
+	"image"
+	"image/gif"
+	"image/jpeg"
+	"image/png"
+	"io"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+// MapImgFmtExts is a map of the image formats and its extensions.
+type MapImgFmtExts map[ImgFmt]Exts
+
+// Exts is a slice of image extensions.
+type Exts []Ext
+
+// Ext is a image extension.
+type Ext string
+
+// ImgFmt is a image format.
+type ImgFmt string
+
+// Converter is a struct which contains info about image formats and extensions.
+type Converter struct {
+	fmtFrom    ImgFmt
+	fmtTo      ImgFmt
+	imgFmtExts MapImgFmtExts
+}
+
+// Convert recursively seeks a given directory and converts images from and to given formats.
+func Convert(dir string, from string, to string) error {
+	if dir == "" {
+		return errors.New("directory name is not provided")
+	}
+
+	cv := &Converter{}
+	cv.imgFmtExts.Init()
+	cv.fmtFrom.Detect(cv, from)
+	cv.fmtTo.Detect(cv, to)
+	if cv.fmtFrom == "" || cv.fmtTo == "" {
+		return errors.New("given image format is not supported")
+	}
+	if cv.fmtFrom == cv.fmtTo {
+		return errors.New("image formats before and after conversion are the same")
+	}
+
+	err := filepath.Walk(dir, func(path string, info os.FileInfo, err error) error {
+		if err != nil {
+			return err
+		}
+
+		err = cv.convSingleFile(path, info)
+		return err
+	})
+	return err
+}
+
+func (cv *Converter) convSingleFile(path string, info os.FileInfo) error {
+	if info.IsDir() {
+		outputPath := addOutputDir(path)
+		return os.MkdirAll(outputPath, 0777)
+	}
+	if !cv.fmtFrom.Match(cv, info.Name()) {
+		return nil
+	}
+
+	f, err := os.Open(path)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+
+	img, err := cv.decodeImg(f)
+	if err != nil {
+		return nil
+	}
+
+	return cv.writeOutputFile(img, path)
+}
+
+func (cv *Converter) writeOutputFile(img image.Image, path string) error {
+	outputPath := cv.generateOutputPath(path)
+
+	f, err := os.Create(outputPath)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+
+	err = cv.encodeImg(f, img)
+	return err
+}
+
+func (cv *Converter) decodeImg(r io.Reader) (image.Image, error) {
+	img, fmtStr, err := image.Decode(r)
+	if ImgFmt(fmtStr) != cv.fmtFrom {
+		err = errors.New("image format does not match")
+	}
+	return img, err
+}
+
+func (cv *Converter) encodeImg(w io.Writer, img image.Image) error {
+	switch cv.fmtTo {
+	case "jpeg":
+		if err := jpeg.Encode(w, img, nil); err != nil {
+			return err
+		}
+	case "png":
+		if err := png.Encode(w, img); err != nil {
+			return err
+		}
+	case "gif":
+		if err := gif.Encode(w, img, nil); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func (cv *Converter) generateOutputPath(path string) string {
+	dirAndBase := strings.TrimRight(path, filepath.Ext(path))
+	ext := cv.imgFmtExts.ConvToExt(cv.fmtTo)
+	path = strings.Join([]string{dirAndBase, string(ext)}, ".")
+	return addOutputDir(path)
+}
+
+func addOutputDir(path string) string {
+	return strings.Join([]string{
+		"./output",
+		strings.TrimLeft(path, "./"),
+	}, "/")
+}
+
+// Detect specifies image format from file extension string.
+func (imgFmt *ImgFmt) Detect(cv *Converter, extStr string) {
+	ext := Ext(strings.ToLower(extStr))
+	*imgFmt = cv.imgFmtExts.ConvToImgFmt(ext)
+}
+
+// Match checks whether the file has an extension of the image format.
+func (imgFmt ImgFmt) Match(cv *Converter, fileName string) bool {
+	fileExtStr := strings.TrimPrefix(filepath.Ext(fileName), ".")
+	fileExt := Ext(strings.ToLower(fileExtStr))
+	fileImgFmt := cv.imgFmtExts.ConvToImgFmt(fileExt)
+	return fileImgFmt == imgFmt
+}
+
+// Init creates the map of image formats and its extensions available.
+func (m *MapImgFmtExts) Init() {
+	*m = MapImgFmtExts{
+		"jpeg": Exts{"jpg", "jpeg"},
+		"png":  Exts{"png"},
+		"gif":  Exts{"gif"},
+	}
+}
+
+// ConvToImgFmt converts image extension to its format.
+func (m MapImgFmtExts) ConvToImgFmt(ext Ext) ImgFmt {
+	for imgFmt, fmtExts := range m {
+		for _, fmtExt := range fmtExts {
+			if ext == fmtExt {
+				return imgFmt
+			}
+		}
+	}
+	return ""
+}
+
+// ConvToExt converts image format to its extension.
+func (m MapImgFmtExts) ConvToExt(imgFmt ImgFmt) Ext {
+	for keyImgFmt, fmtExts := range m {
+		if imgFmt == keyImgFmt {
+			return fmtExts[0]
+		}
+	}
+	return ""
+}
diff --git a/kadai2/lfcd85/imgconv/imgconv_test.go b/kadai2/lfcd85/imgconv/imgconv_test.go
new file mode 100644
index 0000000..a1927f4
--- /dev/null
+++ b/kadai2/lfcd85/imgconv/imgconv_test.go
@@ -0,0 +1,179 @@
+package imgconv
+
+import (
+	"os"
+	"strings"
+	"testing"
+)
+
+func assertEq(t *testing.T, actual interface{}, expected interface{}) {
+	t.Helper()
+	if actual != expected {
+		t.Errorf("actual: %v, expected: %v", actual, expected)
+	}
+}
+
+func assertFileExists(t *testing.T, filePath string, expected bool) {
+	t.Helper()
+
+	_, err := os.Stat(filePath)
+	actual := err == nil
+
+	if actual != expected {
+		switch expected {
+		case true:
+			t.Errorf("file %v should exist but does not", filePath)
+		case false:
+			t.Errorf("file %v should not exist but does", filePath)
+		}
+	}
+}
+
+func TestConvert(t *testing.T) {
+	cases := []struct {
+		from              string
+		to                string
+		expectedSuccess   bool
+		expectedFileNames map[string]bool
+	}{
+		{"jpeg", "png", true, map[string]bool{
+			"not_image.png":         false,
+			"not_image2.png":        false,
+			"sample1.png":           true,
+			"sample2.png":           true,
+			"sample4.png":           false,
+			"child_dir/sample3.png": true,
+			"child_dir/sample4.png": false,
+			"child_dir/sample5.png": false,
+		}},
+		{"png", "gif", true, map[string]bool{
+			"not_image.gif":         false,
+			"not_image2.gif":        false,
+			"sample1.gif":           false,
+			"sample2.gif":           false,
+			"sample4.gif":           true,
+			"child_dir/sample3.gif": false,
+			"child_dir/sample4.gif": true,
+			"child_dir/sample5.gif": false,
+		}},
+		{"gif", "jpeg", true, map[string]bool{
+			"not_image.jpg":         false,
+			"not_image2.jpg":        false,
+			"sample1.jpg":           false,
+			"sample2.jpg":           false,
+			"sample4.jpg":           false,
+			"child_dir/sample3.jpg": false,
+			"child_dir/sample4.jpg": false,
+			"child_dir/sample5.jpg": true,
+		}},
+		{"jpeg", "jpeg", false, nil},
+		{"rb", "go", false, nil},
+	}
+
+	outputDir := "./output/testdata"
+	for _, c := range cases {
+		c := c
+		t.Run(strings.Join([]string{c.from, c.to}, "->"), func(t *testing.T) {
+			defer os.RemoveAll("./output")
+
+			err := Convert("../testdata", c.from, c.to)
+			if err != nil && c.expectedSuccess == true {
+				t.Errorf("function Convert is expected to succeed, but actually failed")
+			}
+			if err == nil && c.expectedSuccess == false {
+				t.Errorf("function Convert is expected to fail, but actually succeeded")
+			}
+			for f, b := range c.expectedFileNames {
+				filePath := strings.Join([]string{outputDir, f}, "/")
+				assertFileExists(t, filePath, b)
+			}
+		})
+	}
+}
+
+func TestConverter_GenerateOutputPath(t *testing.T) {
+	cases := []struct {
+		path     string
+		fmtTo    ImgFmt
+		expected string
+	}{
+		{
+			"path/to/hoge.jpg",
+			ImgFmt("png"),
+			"./output/path/to/hoge.png",
+		},
+		{
+			"./path/to/fuga.PNG",
+			ImgFmt("jpeg"),
+			"./output/path/to/fuga.jpg",
+		},
+		{
+			"piyo.png",
+			ImgFmt("gif"),
+			"./output/piyo.gif",
+		},
+		{
+			"../../path/to/foobar.gif",
+			ImgFmt("jpeg"),
+			"./output/path/to/foobar.jpg",
+		},
+	}
+
+	cv := &Converter{}
+	cv.imgFmtExts.Init()
+	for _, c := range cases {
+		c := c
+		t.Run(c.path, func(t *testing.T) {
+			cv.fmtTo = c.fmtTo
+			assertEq(t, cv.generateOutputPath(c.path), c.expected)
+		})
+	}
+}
+
+func TestImgFmt_Detect(t *testing.T) {
+	cases := []struct {
+		extStr   string
+		expected ImgFmt
+	}{
+		{"png", ImgFmt("png")},
+		{"jpg", ImgFmt("jpeg")},
+		{"JPEG", ImgFmt("jpeg")},
+		{"GIF", ImgFmt("gif")},
+	}
+
+	cv := &Converter{}
+	cv.imgFmtExts.Init()
+	for _, c := range cases {
+		c := c
+		t.Run(c.extStr, func(t *testing.T) {
+			var imgFmt ImgFmt
+			imgFmt.Detect(cv, c.extStr)
+			assertEq(t, imgFmt, c.expected)
+		})
+	}
+}
+
+func TestImgFmt_Match(t *testing.T) {
+	cases := []struct {
+		fileName string
+		imgFmt   ImgFmt
+		expected bool
+	}{
+		{"hoge.jpg", ImgFmt("jpeg"), true},
+		{"fuga.png", ImgFmt("gif"), false},
+		{"piyo.png", ImgFmt("png"), true},
+		{"foo.js", ImgFmt("png"), false},
+		{".JPEG", ImgFmt("jpeg"), true},
+		{"jpeg", ImgFmt("jpeg"), false},
+		{"foopng", ImgFmt("png"), false},
+	}
+
+	cv := &Converter{}
+	cv.imgFmtExts.Init()
+	for _, c := range cases {
+		c := c
+		t.Run(c.fileName, func(t *testing.T) {
+			assertEq(t, c.imgFmt.Match(cv, c.fileName), c.expected)
+		})
+	}
+}
diff --git a/kadai2/lfcd85/testdata/child_dir/not_image.txt b/kadai2/lfcd85/testdata/child_dir/not_image.txt
new file mode 100644
index 0000000..b8d665d
--- /dev/null
+++ b/kadai2/lfcd85/testdata/child_dir/not_image.txt
@@ -0,0 +1 @@
+This is a text file, not an image.
diff --git a/kadai2/lfcd85/testdata/child_dir/not_image2.jpg b/kadai2/lfcd85/testdata/child_dir/not_image2.jpg
new file mode 100644
index 0000000..ad89fab
--- /dev/null
+++ b/kadai2/lfcd85/testdata/child_dir/not_image2.jpg
@@ -0,0 +1 @@
+This file has a extension of jpg, but actually is a text file.
diff --git a/kadai2/lfcd85/testdata/child_dir/sample3.jpg b/kadai2/lfcd85/testdata/child_dir/sample3.jpg
new file mode 100644
index 0000000..2bf5645
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diff --git a/kadai2/lfcd85/testdata/child_dir/sample4.png b/kadai2/lfcd85/testdata/child_dir/sample4.png
new file mode 100644
index 0000000..a5d38d7
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diff --git a/kadai2/lfcd85/testdata/child_dir/sample5.gif b/kadai2/lfcd85/testdata/child_dir/sample5.gif
new file mode 100644
index 0000000..6275211
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diff --git a/kadai2/lfcd85/testdata/sample1.jpg b/kadai2/lfcd85/testdata/sample1.jpg
new file mode 100644
index 0000000..dd33dfe
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diff --git a/kadai2/lfcd85/testdata/sample2.jpg b/kadai2/lfcd85/testdata/sample2.jpg
new file mode 100644
index 0000000..f143791
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diff --git a/kadai2/lfcd85/testdata/sample4.png b/kadai2/lfcd85/testdata/sample4.png
new file mode 100644
index 0000000..62a6b15
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