Big THANK YOU for this addon. This is really important. Unfortunately the resize of the popup is not working for me. The icon in the popup is there, a click on it seems to do something, but no "Popup window sizing" like in your image appear.

Update: now, with v1.7.1, it works like it should. Good job.
Maybe the last position of the popup could be also saved (for me more centered). But we have now what we need.

Update: 1.8.1 with saved position. Great! *Thumbs up
Maybe it would be good if in the popups the pictures had the same height. That way the popup (with certain dimensions) can show the same info for each picture. At the moment you have to scroll down for info on large images.

Thanks for the addon. Its insane that firefox removed this very important feature.

Great, thank you for bringing this back! The original context menu item was needlessly removed from Firefox. The popup could look a little more modern, but that's just optional fluff. The important stuff is there now and that's what matters.
Update: Popup looks great now!

It could be more aesthetically pleasing (nicer icons, better pop-up window layout, and a pop-up window that isn't 100% tall) but it works! :)
Thank you for your work against the dumbing down of Firefox!

2.The "View Image Info..." item does not appear in the context menu for linked images

Edit: #2 example is upper left corner firefox icon in this page(or, https://news.daum.net/ranking/popular).
xIFr(https://addons.mozilla.org/en-US/firefox/addon/xifr/) addon support both features.

Edit2: Thanks for "Last modified:" feature in v1.5.

Following the further dumbing down of Firefox by the removal of 'View Image Info' in the right click context menu of v87, I am pleased to say that this extension makes a very good replacement.