diff --git a/.github/workflows/build-release.yml b/.github/workflows/build-release.yml
index b68d29b..835b0aa 100644
--- a/.github/workflows/build-release.yml
+++ b/.github/workflows/build-release.yml
@@ -66,3 +66,8 @@ jobs:
         with:
           name: dist
           path: dist
+
+      - name: 🧹 Check formatting
+        run: |
+          go fmt ./...
+          git diff --exit-code
diff --git a/cmd/splashscreen-changer/config_test.go b/cmd/splashscreen-changer/config_test.go
new file mode 100644
index 0000000..5bf5ced
--- /dev/null
+++ b/cmd/splashscreen-changer/config_test.go
@@ -0,0 +1,225 @@
+package main
+
+import (
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+)
+
+func TestLoadConfig(t *testing.T) {
+	// Create necessary directories
+	tmpDir := os.TempDir()
+	sourceDirPath := filepath.Join(tmpDir, "source")
+	if err := os.MkdirAll(sourceDirPath, os.ModePerm); err != nil {
+		t.Fatalf("Failed to create source directory: %v", err)
+	}
+	defer func() {
+		if err := os.RemoveAll(sourceDirPath); err != nil {
+			t.Errorf("Failed to remove source directory: %v", err)
+		}
+	}()
+	destinationDirPath := filepath.Join(tmpDir, "destination")
+	if err := os.MkdirAll(filepath.Join(destinationDirPath, "EasyAntiCheat"), os.ModePerm); err != nil {
+		t.Fatalf("Failed to create destination directory: %v", err)
+	}
+	defer func() {
+		if err := os.RemoveAll(destinationDirPath); err != nil {
+			t.Fatalf("Failed to remove destination directory: %v", err)
+		}
+	}()
+
+	// Create a temporary config file
+	configContent := `
+source:
+	path: {{ .Source.Path }}
+	recursive: true
+destination:
+	path: {{ .Destination.Path }}
+	width: 1024
+	height: 768
+`
+	configContent = strings.TrimSpace(configContent)
+	configContent = strings.ReplaceAll(configContent, "\t", "  ")
+	configContent = strings.ReplaceAll(configContent, "{{ .Source.Path }}", sourceDirPath)
+	configContent = strings.ReplaceAll(configContent, "{{ .Destination.Path }}", destinationDirPath)
+
+	tmpFile, err := os.CreateTemp("", "config-*.yaml")
+	if err != nil {
+		t.Fatalf("Failed to create temp file: %v", err)
+	}
+	defer os.Remove(tmpFile.Name())
+
+	if _, err := tmpFile.Write([]byte(configContent)); err != nil {
+		t.Fatalf("Failed to write to temp file: %v", err)
+	}
+	if err := tmpFile.Close(); err != nil {
+		t.Fatalf("Failed to close temp file: %v", err)
+	}
+
+	// Load the config
+	config, err := LoadConfig(tmpFile.Name())
+	if err != nil {
+		t.Fatalf("Failed to load config: %v", err)
+	}
+
+	// Check the loaded config values
+	if config.Source.Path != filepath.Join(tmpDir, "source") {
+		t.Errorf("Expected source path to be '%s', got '%s'", filepath.Join(tmpDir, "source"), config.Source.Path)
+	}
+	if !config.Source.Recursive {
+		t.Errorf("Expected source recursive to be true, got false")
+	}
+	if config.Destination.Path != filepath.Join(tmpDir, "destination") {
+		t.Errorf("Expected destination path to be '%s', got '%s'", filepath.Join(tmpDir, "destination"), config.Destination.Path)
+	}
+	if config.Destination.Width != 1024 {
+		t.Errorf("Expected destination width to be 1024, got %d", config.Destination.Width)
+	}
+	if config.Destination.Height != 768 {
+		t.Errorf("Expected destination height to be 768, got %d", config.Destination.Height)
+	}
+}
+
+func TestLoadConfigWithDefaults(t *testing.T) {
+	// Create necessary directories
+	tmpDir := os.TempDir()
+	sourceDirPath := filepath.Join(tmpDir, "source")
+	os.MkdirAll(sourceDirPath, os.ModePerm)
+	defer os.RemoveAll(sourceDirPath)
+	destinationDirPath := filepath.Join(tmpDir, "destination")
+	os.MkdirAll(filepath.Join(destinationDirPath, "EasyAntiCheat"), os.ModePerm)
+	defer os.RemoveAll(destinationDirPath)
+
+	// Create a temporary config file
+	configContent := `
+source:
+	path: {{ .Source.Path }}
+destination:
+	path: {{ .Destination.Path }}
+`
+	configContent = strings.TrimSpace(configContent)
+	configContent = strings.ReplaceAll(configContent, "\t", "  ")
+	configContent = strings.ReplaceAll(configContent, "{{ .Source.Path }}", sourceDirPath)
+	configContent = strings.ReplaceAll(configContent, "{{ .Destination.Path }}", destinationDirPath)
+
+	tmpFile, err := os.CreateTemp("", "config-*.yaml")
+	if err != nil {
+		t.Fatalf("Failed to create temp file: %v", err)
+	}
+	defer os.Remove(tmpFile.Name())
+
+	if _, err := tmpFile.Write([]byte(configContent)); err != nil {
+		t.Fatalf("Failed to write to temp file: %v", err)
+	}
+	if err := tmpFile.Close(); err != nil {
+		t.Fatalf("Failed to close temp file: %v", err)
+	}
+
+	// Load the config
+	config, err := LoadConfig(tmpFile.Name())
+	if err != nil {
+		t.Fatalf("Failed to load config: %v", err)
+	}
+
+	// Check the loaded config values
+	if config.Source.Path != filepath.Join(tmpDir, "source") {
+		t.Errorf("Expected source path to be '%s', got '%s'", filepath.Join(tmpDir, "source"), config.Source.Path)
+	}
+	if config.Source.Recursive {
+		t.Errorf("Expected source recursive to be false, got true")
+	}
+	if config.Destination.Path != filepath.Join(tmpDir, "destination") {
+		t.Errorf("Expected destination path to be '%s', got '%s'", filepath.Join(tmpDir, "destination"), config.Destination.Path)
+	}
+	if config.Destination.Width != 800 {
+		t.Errorf("Expected destination width to be 800, got %d", config.Destination.Width)
+	}
+	if config.Destination.Height != 450 {
+		t.Errorf("Expected destination height to be 450, got %d", config.Destination.Height)
+	}
+}
+
+func TestLoadConfigWithEnvOverrides(t *testing.T) {
+	// Create necessary directories
+	tmpDir := os.TempDir()
+	envSourceDirPath := filepath.Join(tmpDir, "env", "source")
+	os.MkdirAll(envSourceDirPath, os.ModePerm)
+	defer os.RemoveAll(envSourceDirPath)
+	envDestinationDirPath := filepath.Join(tmpDir, "env", "destination")
+	os.MkdirAll(filepath.Join(envDestinationDirPath, "EasyAntiCheat"), os.ModePerm)
+	defer os.RemoveAll(envDestinationDirPath)
+	configSourceDirPath := filepath.Join(tmpDir, "source")
+	os.MkdirAll(configSourceDirPath, os.ModePerm)
+	defer os.RemoveAll(configSourceDirPath)
+	configDestinationDirPath := filepath.Join(tmpDir, "destination")
+	os.MkdirAll(filepath.Join(configDestinationDirPath, "EasyAntiCheat"), os.ModePerm)
+	defer os.RemoveAll(configDestinationDirPath)
+
+	// Set environment variables
+	customEnv := map[string]string{
+		"SOURCE_PATH":        envSourceDirPath,
+		"SOURCE_RECURSIVE":   "true",
+		"DESTINATION_PATH":   envDestinationDirPath,
+		"DESTINATION_WIDTH":  "1280",
+		"DESTINATION_HEIGHT": "720",
+	}
+	for key, value := range customEnv {
+		os.Setenv(key, value)
+	}
+	defer func() {
+		for key := range customEnv {
+			os.Unsetenv(key)
+		}
+	}()
+
+	// Create a temporary config file
+	configContent := `
+source:
+	path: {{ .Source.Path }}
+	recursive: false
+destination:
+	path: {{ .Destination.Path }}
+	width: 1024
+	height: 768
+`
+	configContent = strings.TrimSpace(configContent)
+	configContent = strings.ReplaceAll(configContent, "\t", "  ")
+	configContent = strings.ReplaceAll(configContent, "{{ .Source.Path }}", configSourceDirPath)
+	configContent = strings.ReplaceAll(configContent, "{{ .Destination.Path }}", configDestinationDirPath)
+	tmpFile, err := os.CreateTemp("", "config-*.yaml")
+	if err != nil {
+		t.Fatalf("Failed to create temp file: %v", err)
+	}
+	defer os.Remove(tmpFile.Name())
+
+	if _, err := tmpFile.Write([]byte(configContent)); err != nil {
+		t.Fatalf("Failed to write to temp file: %v", err)
+	}
+	if err := tmpFile.Close(); err != nil {
+		t.Fatalf("Failed to close temp file: %v", err)
+	}
+
+	// Load the config
+	config, err := LoadConfig(tmpFile.Name())
+	if err != nil {
+		t.Fatalf("Failed to load config: %v", err)
+	}
+
+	// Check the loaded config values
+	if config.Source.Path != envSourceDirPath {
+		t.Errorf("Expected source path to be '%s', got '%s'", envSourceDirPath, config.Source.Path)
+	}
+	if !config.Source.Recursive {
+		t.Errorf("Expected source recursive to be true, got false")
+	}
+	if config.Destination.Path != envDestinationDirPath {
+		t.Errorf("Expected destination path to be '%s', got '%s'", envDestinationDirPath, config.Destination.Path)
+	}
+	if config.Destination.Width != 1280 {
+		t.Errorf("Expected destination width to be 1280, got %d", config.Destination.Width)
+	}
+	if config.Destination.Height != 720 {
+		t.Errorf("Expected destination height to be 720, got %d", config.Destination.Height)
+	}
+}
diff --git a/cmd/splashscreen-changer/main_test.go b/cmd/splashscreen-changer/main_test.go
new file mode 100644
index 0000000..bcccfaf
--- /dev/null
+++ b/cmd/splashscreen-changer/main_test.go
@@ -0,0 +1,112 @@
+package main
+
+import (
+	"image"
+	"image/png"
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+// Test listPNGFiles function
+func TestListPNGFiles(t *testing.T) {
+	// Create a temporary directory
+	tmpDir := os.TempDir()
+	tmpDir = filepath.Join(tmpDir, "listPNGFiles")
+	os.Mkdir(tmpDir, os.ModePerm)
+
+	// Create some test PNG files
+	file1, _ := os.Create(filepath.Join(tmpDir, "test1.png"))
+	file1.Close()
+	file2, _ := os.Create(filepath.Join(tmpDir, "test2.png"))
+	file2.Close()
+
+	// Create a non-PNG file
+	file3, _ := os.Create(filepath.Join(tmpDir, "test3.txt"))
+	file3.Close()
+
+	// Test non-recursive listing
+	files, err := listPNGFiles(tmpDir, false)
+	if err != nil {
+		t.Fatalf("Expected no error, got %v", err)
+	}
+	if len(files) != 2 {
+		t.Fatalf("Expected 2 PNG files, got %d", len(files))
+	}
+
+	// Test recursive listing
+	subDir := filepath.Join(tmpDir, "subdir")
+	os.Mkdir(subDir, 0755)
+	file4, _ := os.Create(filepath.Join(subDir, "test4.png"))
+	file4.Close()
+
+	files, err = listPNGFiles(tmpDir, true)
+	if err != nil {
+		t.Fatalf("Expected no error, got %v", err)
+	}
+	if len(files) != 3 {
+		t.Fatalf("Expected 3 PNG files, got %d", len(files))
+	}
+}
+
+// Test pickRandomFile function
+func TestPickRandomFile(t *testing.T) {
+	files := []string{"file1.png", "file2.png", "file3.png"}
+	pickedFile, err := pickRandomFile(files)
+	if err != nil {
+		t.Fatalf("Expected no error, got %v", err)
+	}
+	if pickedFile == "" {
+		t.Fatalf("Expected a file to be picked, got an empty string")
+	}
+
+	// Test with empty list
+	files = []string{}
+	_, err = pickRandomFile(files)
+	if err == nil {
+		t.Fatalf("Expected an error, got nil")
+	}
+}
+
+// Test cropToAspectRatio function
+func TestCropToAspectRatio(t *testing.T) {
+	img := image.NewRGBA(image.Rect(0, 0, 100, 200))
+	croppedImg := cropToAspectRatio(img, 50, 50)
+
+	if croppedImg.Bounds().Dx() != 50 || croppedImg.Bounds().Dy() != 50 {
+		t.Fatalf("Expected cropped image to be 50x50, got %dx%d", croppedImg.Bounds().Dx(), croppedImg.Bounds().Dy())
+	}
+}
+
+// Test resizePNGFile function
+func TestResizePNGFile(t *testing.T) {
+	// Create a temporary directory
+	tempDir := os.TempDir()
+
+	// Create a test PNG file
+	srcPath := filepath.Join(tempDir, "src.png")
+	destPath := filepath.Join(tempDir, "dest.png")
+
+	img := image.NewRGBA(image.Rect(0, 0, 100, 200))
+	f, _ := os.Create(srcPath)
+	png.Encode(f, img)
+	f.Close()
+
+	err := resizePNGFile(srcPath, destPath, 50, 50)
+	if err != nil {
+		t.Fatalf("Expected no error, got %v", err)
+	}
+
+	// Check if the destination file exists
+	if _, err := os.Stat(destPath); os.IsNotExist(err) {
+		t.Fatalf("Expected destination file to exist, but it does not")
+	}
+
+	// Check if the destination file has the correct dimensions
+	destFile, _ := os.Open(destPath)
+	defer destFile.Close()
+	destImg, _, _ := image.Decode(destFile)
+	if destImg.Bounds().Dx() != 50 || destImg.Bounds().Dy() != 50 {
+		t.Fatalf("Expected resized image to be 50x50, got %dx%d", destImg.Bounds().Dx(), destImg.Bounds().Dy())
+	}
+}