   renderPreload: ->
     <div style={@PRELOAD_STYLE}>
       {for image in @props.images
-        <img src={image} />}
+        <img src={image} key={image} />}
     </div>
 
   handleFrameChange: (frame) ->

      <img src={@props.images[@state.frame]} className="survey-task-image-flipper-image" />
      <span className="survey-task-image-flipper-pips">
        {for index in [0...@props.images.length]
          <span>
            <button type="button" className="survey-task-image-flipper-pip" disabled={index is @state.frame} onClick={@handleFrameChange.bind this, index}>{index + 1}</button>
            {' '}
          </span>}

        else
          for choiceID, i in filteredChoices
            choice = @props.task.choices[choiceID]
            <button key={choiceID + i} type="button" className="survey-task-chooser-choice" onClick={@props.onChoose.bind null, choiceID}>
              {unless choice.images.length is 0
                  <img src={choice.images[0]} className="survey-task-chooser-choice-thumbnail" />}
              <div className="survey-task-chooser-choice-label">{choice.label}</div>
