I don't know when they started but for quite awhile now (months, more likely years) imgbox has stored the original filename of an image in the
title attribute:
Code:
<div class="image-container">
<img alt="4cjqlip9" class="image-content" id="img" onclick="rs()" src="https://i.imgbox.com/4cjQLIp9.jpg" title="Bettie_Page_Classic_Nude_Pinup.jpg" />
</div>
If one right-clicks on the above image (from the
page url, that is) I get the correct image filename in the save-as box. I also get the correct image filename when right-clicking from the direct image link.
I also get the correct filename when right-clicking from retroanalyst's linked gif: "unacceptable.gif".
The underscores has also been a "feature" of imgbox for some years--spaces and commas get replaced. Maybe other chars. as well, I haven't studied.
So: I'm not sure what the problem is that you've found?