HI Sranjan,
You have not selected any image in FS_REFERENCE component.
<FS_REFERENCE
name="st_picture"
------
----------
</FS_REFERENCE>
$CMS_IF(!st_picture.isEmpty)$
<div class="bottom">
<img src="$CMS_REF(st_picture,resolution:"rsImage")$">
</div>
$CMS_END_IF$
In the above code if required use resolution else omit it.
one more point check for Image is a language dependent or not.If yes then check for page language all the pages image is selected properly. If not also we get the error.
I hope this will help you.