I have installed wintricks & also followed the guidelines of this question's => Answer. But I'm getting this problem => (Check the print screen I have shared below)
404 NOT FOUND on your download of the Picasa installer means that the installer is not present at the requested URL.
This is less an Ubuntu issue, and more an issue of Picasa/Google's side.
HOWEVER, according to https://picasa.google.com/:
Moving on from Picasa
We’ve decided to retire Picasa in order to focus on a single photo service in Google Photos – a new, smarter photo app that works seamlessly across mobile and the web.
Therefore, you are no longer able to get Picasa from Google, and instead need to use the Google Photos system, which has no local application for it. (Which means that you cannot install Picasa anymore anywhere)