You need to link your main image:
https://www.curtainsstore.in/web/wp-content/uploads/2011/02/0102-300×232.jpg
to the large version of that image.
At present, there is no link.
Your HTML at present is:
<img class="alignnone size-medium wp-image-895" title="010" src="https://www.curtainsstore.in/web/wp-content/uploads/2011/02/0102-300x232.jpg" alt="" width="300" height="232" />
Change it to:
<a href="your-big-image.jpg" class="MagicZoom"><img class="alignnone size-medium wp-image-895" title="010" src="https://www.curtainsstore.in/web/wp-content/uploads/2011/02/0102-300x232.jpg" alt="" width="300" height="232" /></a>
where “your-big-image.jpg” is the location of your large image.