added screenshots

browser.go

@@ -5,8 +5,23 @@ import (
 	"io"
 )
 
+type ScreenshotStyle string
+
+const (
+	ScreenshotStyleFullPage ScreenshotStyle = "full"
+	ScreenshotStyleViewport ScreenshotStyle = "viewport"
+)
+
+type ScreenshotOptions struct {
+	Style  ScreenshotStyle
+	Width  int
+	Height int
+}
+
 type Browser interface {
 	io.Closer
 
 	Open(ctx context.Context, url string) (Source, error)
+	Screenshot(ctx context.Context, url string, opts ScreenshotOptions) ([]byte, error)
+	OpenAndScreenshot(ctx context.Context, url string, opts ScreenshotOptions) (Source, []byte, error)
 }