Thanks for replying vijay.I did as you suggested

<a href="PATH\HIGH_RES_IMAGE_NAME">Download High resolution image</a>

With that, on click of hyperlink the image gets opened up in same browser window and doesnot pop up for download.

I tried giving path using 'http' and mentioning the drive:
<a href="http://server_name/images/HIGH_RES_IMAGE_NAME.gif">Download High resolution image</a>

<a href="f:/images/HIGH_RES_IMAGE_NAME.gif">Download High resolution image</a>

Priti