What is a good alternative to using an image map generator?

Why don’t you use a combination of HTML/CSS instead? Image maps are obsolete.

This btw is Search Engine Optimised as well 🙂

Source code follows:

.image-map {
  background: url('https://www.google.com/images/branding/googlelogo/1x/googlelogo_color_272x92dp.png');
  width: 272px;
  height: 92px;
  display: block;
  position: relative;
  margin-top:10px;
  float: left;
}

.image-map > a.map {
  position: absolute;
  display: block;
  border: 1px solid green;
}

<div class="image-map">
    <a class="map" rel="G" style="top: 0px; left: 0px; width: 70px; height: 95px;" href="#"></a>
    <a class="map" rel="o" style="top: 0px; left: 70px; width: 50px; height: 95px" href="#"></a>
    <a class="map" rel="o" style="top: 0px; left: 120px; width: 50px; height: 95px" href="#"></a>
    <a class="map" rel="g" style="top: 0px; left: 170px; width: 40px; height: 95px" href="#"></a>
    <a class="map" rel="l" style="top: 0px; left: 210px; width: 20px; height: 95px" href="#"></a>
    <a class="map" rel="e" style="top: 0px; left: 230px; width: 40px; height: 95px" href="#"></a>
</div>

EDIT:

After the numerous negative points this answer has received I have to come back and say that I can clearly see that you don’t agree with my answer, but I personally still believe that is a better option than image maps.

Sure it cannot do polygons, it might have issues on manual page zoom, but personally I feel image maps are obsolete although still on the html5 specification. (It makes make more sense nowadays to try and replicate them using html5 canvas instead)

However I guess the target audience for this question does not agree with me.

You could also check this Are HTML Image Maps still used? and see the most highly voted answer just for reference.