REGARDING : This review by 12503762, 8 mths ago :

Would it be possible to add Base64 image support
(the data:image/png;base64 type of files for example)?
Also this extension has the same bug as the old ImageZoom extension,
on some images when you have them directly open in the page (direct link to image file),
when you zoom in it progressively crops the top of the image you can't see it at all.
Here is an image to show what I mean :
http://lesfouleesdelasfas.fr/wp-content/uploads/2017/10/bryan_cranston_0095.jpg
with this big image, depending on actions I do (direct zoom with clicks combination or mouse wheel)
It happens that the top of the image is not visible anymore, image seems to start from the middle of it.

· · · · V · · V · · V · · V · · V · · V · · V · · V · · V · · V · · V · · · ·

What I (Oby) noticed is I can right click on the photo image of Bryan Cranston that appears after I use
"Zoom Image by Amu" 2x zoom, & drag it it down, then
the full TOP of the picture also drags into view.

I don't know why the scroll bar won't allow me to get to the top.

Maybe it's to do with Firefox screen size handling / zoom,
versus CSS-based screen-size handling / zoom.
Well, at least I took the time to make this post. B^)