title: Openlayers 5 add feature images
body: <p>I want to add an images like vector feature to map.
  Now I use this code:</p>
  
  <pre><code>const format = new WKT()
  for (let i=0; i&lt;previews.length; i++)
      let vectorFeature = format.readFeature(previews[i].polygon, {
           dataProjection: 'EPSG:4326',
           featureProjection: 'EPSG:3857'
      })
      let imageLayer = new ImageLayer({
          source: new Static({
              attributions: 'attributions',
              url: '/10103996_'+(i+1)+'.png',
              projection: mapProjection,
              imageExtent: vectorFeature.getGeometry().getExtent()
          })
      })
  </code></pre>
  
  <p>And previews have structure like this:</p>
  
  <pre><code>"previews": [{
              "file_name": url + "10103996_1.png",
              "polygon": "MULTIPOLYGON(((84.7750652694291 56.1279268975274,86.6554085015044 56.1279268975274,86.6554085015044 55.0621305005073,84.7750652694291 55.0621305005073,84.7750652694291 56.1279268975274)))"
          }, {
              "file_name": url + "10103996_2.png",
              "polygon": "MULTIPOLYGON(((84.4341862638055 55.2868953528938,86.2427851333094 55.2868953528938,86.2427851333094 54.2884096525321,84.4341862638055 54.2884096525321,84.4341862638055 55.2868953528938)))"
          }]
  </code></pre>
  
  <p>In Openlayers 2 there is a solution to add an images to vector contour:</p>
  
  <pre><code>OpenLayers.Feature.ImageFeature = OpenLayers.Class(OpenLayers.Feature.Vector, {
      previews: null,
      previewsVisibility: false,
      visibility: true,
      initialize: function(options){ 
          OpenLayers.Feature.Vector.prototype.initialize.call(this, options.geometry, options.attributes, options.style);
          this.fid = options.fid;
          this.previews = [];
          this.previewsVisibility = options.previewVisibility || false;
  
          Ext.each(options.previews, function(preview) {
              var g = OpenLayers.Geometry.fromWKT(preview.polygon);
              g = g.transform("EPSG:4326", "EPSG:3857");
  
              this.addPreview(g, preview.fileName);
          }, this);
      },
      addPreview: function(geometry, url){
          if (Ext.isNumber(Ext.each(this.previews, function(feature){
              return feature.attributes.previewOriginalUrl != url;
          }, this))) return;
          var vertices = geometry.getVertices();
          var preview = new OpenLayers.Feature.Vector(
              geometry.getCentroid(),
              {
                  width: vertices[0].distanceTo(vertices[1]),
                  height: vertices[1].distanceTo(vertices[2]),
                  alpha: Math.atan2(vertices[1].y - vertices[0].y, vertices[1].x - vertices[0].x),
                  previewOriginalUrl: url,
                  previewUrl: url +"?r=" + Math.random(),
                  render: "drawAlways"
              });
          preview.selectable = false;
          this.previews.push(preview);
      },
      CLASS_NAME: "OpenLayers.Feature.Vector"
  });
  </code></pre>
  
  <p>What classes i need to use for add more than 1 image feature to layer?</p>