How can I add multiple images along with other input fields in vue js html?

I'm not sure where would you like the extra images to appear, but I added them after this column:

<div class="col-md-4">
  <div class="button success expand radius">
    <span id="save_image_titlebar_logo_live">Recent Photograph</span>
    <label class="custom-file-upload">
  <input type="file" name="sign"/>
  </label>
  </div>
</div>

And here's the column I added — "add images": (You can try this feature here, with the updates)

<div class="col-md-4">
  <ul class="list-group" :if="images.length">
    <li class="list-group-item" v-for="(f, index) in images" :key="index">
      <button class="close" @click.prevent="removeImage(index, $event)">&times;</button>
      <div class="button success expand radius">
        <label class="custom-file-upload">
          <input type="file" class="images[]" accept="image/*" @change="previewImage(index, $event)">
        </label>
      </div>
      <div :class="'images[' + index + ']-preview image-preview'"></div>
    </li>
  </ul>
  <button class="btn btn-link add-image" @click.prevent="addNewImage">Add Image</button>
</div>

And the full Vue JS code (with jQuery.ajax()):

addForm = new Vue({
  el: "#addForm",
  data: {
    name: '',
    alias: '',
    sex: '',
    sez: [{
      date: null,
      details: null
    }],
    // I removed `photo` and `sign` because (I think) the're not necessary.
    // Add I added `images` so that we could easily add new images via Vue.
    images: [],
    maxImages: 5,
    // Selector for the "Add Image" button. Try using (or you should use) ID
    // instead; e.g. `button#add-image`. But it has to be a `button` element.
    addImage: 'button.add-image'
  },
  methods: {
    addNewRow: function() {
      // I changed to `this.sez.push` because `this.seziure` is `undefined`.
      this.sez.push({
        date: null,
        details: null
      });
    },

    addNewImage: function(e) {
      var n = this.maxImages || -1;
      if (n && this.images.length < n) {
        this.images.push('');
      }
      this.checkImages();
    },

    removeImage: function(index) {
      this.images.splice(index, 1);
      this.checkImages();
    },

    checkImages: function() {
      var n = this.maxImages || -1;
      if (n && this.images.length >= n) {
        $(this.addImage, this.el).prop('disabled', true);  // Disables the button.
      } else {
        $(this.addImage, this.el).prop('disabled', false); // Enables the button.
      }
    },

    previewImage: function(index, e) {
      var r = new FileReader(),
        f = e.target.files[0];

      r.addEventListener('load', function() {
        $('[class~="images[' + index + ']-preview"]', this.el).html(
          '<img src="' + r.result + '" class="thumbnail img-responsive">'
        );
      }, false);

      if (f) {
        r.readAsDataURL(f);
      }
    },

    handleSubmit: function(e) {
      var vm = this;

      var data = new FormData(e.target);
      data.append('sez', this.sez);
      data.append('name', this.name);
      data.append('alias', this.alias);
      data.append('sex', this.sex);

      // The `data` already contain the Signature and Recent Photograph images.
      // Here we add the extra images as an array.

      $('[class~="images[]"]', this.el).each(function(i) {
        if (i > vm.maxImages - 1) {
          return; // Max images reached.
        }

        data.append('images[' + i + ']', this.files[0]);
      });

      $.ajax({
        url: 'http://localhost:4000/save/',
        data: data,
        type: 'POST',
        dataType: 'json',
        success: function(e) {
          if (e.status) {
            vm.response = e;
            alert("success");
          } else {
            vm.response = e;
            console.log(vm.response);
            alert("Registration Failed");
          }
        },
        cache: false,
        contentType: false,
        processData: false
      });

      return false;
    },
  },
});

Additional Notes

I know you're using Node.js in the back-end; however, I should mention that in PHP, the $_FILES variable would contain all the images (so long as the fields name are properly set); and I suppose Node.js has a similar variable or way of getting the files.

And in the following input, you may have forgotten to wrap book.details in v-model:

<input type="text" class="form-control" book.details>
<input type="text" class="form-control" v-model="book.details"> <!-- Correct -->

UPDATE

Added feature to limit number of images allowed to be selected/uploaded, and added preview for selected image. Plus the "send images as array" fix.