Wrong BBOX in url for getFeatureInfo in ol.source.ImageWMS 

In <i>source/imagewmssource.js</i>
for <i>ol.source.ImageWMS.prototype.getFeatureInfoForPixel</i>
Extent is Wrong, ymin and xmax are inverted.

      size = map.getSize(),
      bottomLeft = map.getCoordinateFromPixel([0, size[1]]),
      topRight = map.getCoordinateFromPixel([size[0], 0]),
      extent = [bottomLeft[0], topRight[0], bottomLeft[1], topRight[1]],

Must be:
   <i>extent = [bottomLeft[0],  <b>bottomLeft[1], topRight[0]</b>, topRight[1]],</i>

NB: in tiledwmssource.js extent (relative to tile is correctly compute and set in BBOX url part).