Greasy Fork is available in English.
Powerful picture viewing tool online, which can popup/scale/rotate/batch save pictures automatically
< Σχολιασμός για τον κώδικα Picviewer CE+
This comment is for just in case someone encounters this problem in the future. Although clicking off the image to close it may not be added in the future, you can alternatively double-click the image to close it, which I think is just as convenient.
The script works well but one feature that would be nice to add would be the ability to close the image by clicking off of it when you are using the script to preview an image.