Undo "Always display images" switch in Gmail

Gmail has this nifty and very useful feature to avoid mostly annoying images being displayed in our incoming emails. Whenever we get an email containing an embedded image, it is not displayed by default. Instead there appear two links at the top of the email saying:

"Display images below"
"Always display images from <this sender's email>"

The first one is a one time thing and the second one is a setting for that particular email id.

I once clicked on the second link accidentally and had unwanted images cluttering my email view. I looked for this thing to be turned off in the settings page, but found nothing. I had a very hard time undoing this accidental setting. Finally I discovered the solution also accidentally. The switch to undo this setting is "hidden" under the "Show Details" link for the email header.

The right end of the very first line of the email, which contains the sender's name/email id", has this "Show Details" link. This shows the email header with several details. At the end is the link saying something like this:

"Do not display images from this sender".

Just use this switch to go back to the good old times of emails without images. :)