Greasy Fork is available in English.
線上看圖工具，支援圖片翻轉、旋轉、縮放、彈出大圖、批量儲存
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.