如何使用上一步和下一步按钮切换src和onclick？

<button id="prevBtn">上一步</button>
<button id="nextBtn">下一步</button>

var prevBtn = document.getElementById("prevBtn");
var nextBtn = document.getElementById("nextBtn");

prevBtn.addEventListener("click", prevStep);
nextBtn.addEventListener("click", nextStep);

function prevStep() {
  // 切换到上一步
  var img = document.getElementById("image");
  img.src = "previous_image.jpg";
  img.onclick = prevStep;
}

function nextStep() {
  // 切换到下一步
  var img = document.getElementById("image");
  img.src = "next_image.jpg";
  img.onclick = nextStep;
}