Applescript code for rename while save the Document

[Asuvath]

Hi,

For my task, i opened the URL from Photoshop and to get the full page screen shot from safari browser.

On that task, I am sruggling to rename the file through applescript while save as (see below screenshot) in Safari browser.

Can any one look into this and provide the applescript code for save that screen shot as "Small.png" in ~Desktop/Screen_Shot.

Thanks

Asuvath