It works, I've tried some other image download apps and this one is very easy to use!

Exact what i was looking for in terms of functions and also clean, no clutter or nonsens fancy Gfx ui, just perfect.

Thank you a lot! You really save my time!

Unfortunately, a website banned me for ten minutes, after I downloaded 500 images in an hour.
Still, I gave five stars because it is the best in what it does.
If you use it sparingly, it should be fine.
The only things that I modified are:
I check "File size" and in the "Min" field I write 40000.
To have the icon in the toolbar, click "Extensions" (in the toolbar), then the gear on the right of this extension, then "Pin to toolbar".
To use it, click on its icon, then wait until the progress bar stops moving. It never reaches the end. It stops one millimiter sooner. Then click "Save". Then "OK". The images will be in a directory with the name of the website. In a zip file.