Fixed Alt attribute missing in thumb images

[refael]

<div class="thumbnailContainer">

    ...
    <a href="media/big-preview.71/">
        <img src="data/xengallery/youtube/youtube_ILb3Ml90HQk_thumb.jpg?t=1415892671" class="thumbImage" />
    </a>
    ...
</div>

The image here missing alt attribute which is required for this element.
The code is from the index page of the gallery.

 

[Chris D]

I've changed this in the next release, for albums too.