`brew install --cask google-chrome`, `go run ./... `

webdriver_screenshot.go

package main

import (
	"context"
	"log"
	"os"

	"github.com/chromedp/chromedp"
	"github.com/go-rod/rod"
	"github.com/go-rod/rod/lib/launcher"
	"github.com/tebeka/selenium"
)

func main() {
	urlToCapture := "http://example.com/page.html"

	// buf, err := localChrome(urlToCapture)
	// buf, err := remoteSeleniumWebdriverRod(urlToCapture)
	buf, err := remoteSeleniumWebdriverTebeka(urlToCapture)
	if err != nil {
		log.Fatal(err)
	}

	if err := os.WriteFile("screenshot.png", buf, 0644); err != nil {
		log.Fatal(err)
	}
}

func localChrome(url string) ([]byte, error) {
	chromeLocation := "/Applications/Google Chrome.app/Contents/MacOS/Google Chrome"

	opts := append(chromedp.DefaultExecAllocatorOptions[:],
		chromedp.ExecPath(chromeLocation),
		chromedp.WindowSize(800, 480),
	)

	allocCtx, cancel := chromedp.NewExecAllocator(context.Background(), opts...)
	defer cancel()

	ctx, cancel := chromedp.NewContext(allocCtx)
	defer cancel()

	var buf []byte
	if err := chromedp.Run(ctx,
		chromedp.Navigate(url),
		chromedp.FullScreenshot(&buf, 90), // 90 is quality
	); err != nil {
		return nil, err
	}

	return buf, nil
}

func remoteSeleniumWebdriverRod(url string) ([]byte, error) {
	// chromedp doesn't natively support Selenium's WebDriver protocol - it expects direct Chrome DevTools Protocol (CDP) access.
	// You'd need to manually create a session first.
	//
	// The rod library apparently has better Selenium support out of the box.
	// Unfortunately, neither chromedp nor rod work well with Selenium Grid out of the box because they expect direct CDP access, not the WebDriver protocol.
	wsURL := "ws://webdriver.example.com:4444/wd/hub"
	l := launcher.MustResolveURL(wsURL)

	browser := rod.New().ControlURL(l).MustConnect()
	defer browser.MustClose()

	page := browser.MustPage(url).MustSetViewport(800, 480, 1, false)
	buf := page.MustWaitLoad().MustScreenshot()

	return buf, nil
}

func remoteSeleniumWebdriverTebeka(url string) ([]byte, error) {
	wdURL := "https://webdriver.example.com:4444/wd/hub"

	caps := selenium.Capabilities{
		"browserName": "chrome",
	}

	wd, err := selenium.NewRemote(caps, wdURL)
	if err != nil {
		return nil, err
	}
	defer wd.Quit()

	if err := wd.ResizeWindow("", 800, 480); err != nil {
		return nil, err
	}

	if err := wd.Get(url); err != nil {
		return nil, err
	}

	screenshot, err := wd.Screenshot()
	if err != nil {
		return nil, err
	}

	return screenshot, nil
}