Basically, tap and hold on any image, and from the menu shown select the one before last (second from the bottom) option “Zapisz obrazek” (i.e. “Save the image”). When it finishes downloading, a popup notification will be shown. Do not touch it, let it close by itself after a few seconds.
Then repeat it to download another image. When it finishes downloading, see how two notifications are shown one after another instead of just one (not only the second image’s notification is shown but also the previously downloaded image’s notification is repeated). Keep saving more images, and you’ll end up with - say - 10 notifications being repeated one after another.
You need to either dismiss each notification manually when it is shown, or go to the SFOS events screen and clear all those notifications from there, to make them stop being remembered and re-displayed eternally.