I'm actually pretty sure that the original was NOT so small... the forum did it.
The question is now how exactly to reproduce it... the filename of the "miniature" says "PastedImage", i.e. it was apparently NOT uploaded, but pasted from clipboard... also, the format of the pasted "miniature" is .jpeg, as opposed to the .png format of image pasted by me...
The conclusion is pretty clear - the final result of the pasted image depends on particular source of the clipboard content...
And the fact that that there is way TOO MANY of such miniatures all over the forum, having too similar "symptoms", that it simply cannot be caused by USERS making them so small (how exactly would you do such shrinked image in clipboard, especially if we are talking about rather "amateurish" users who - let's tell it straight - have often problems with elementary computer usage, i.e. are hardly expected to be able to fiddle in some advanced way with the clipboard content)