rigete

Excellent work. I checked the function and works very well. You should specify this feature in the plugin description so that all people know.

Thank you very much.

I found these links showing how to watermark images with PHP and GD graphics gallery:

https://www.cf-works.com/PHP-Open-Source/Watermarking-PNG-JPEG-Images-with-PHP-GD2.html

https://nzwhost.com/article/simple-php-watermark

https://gonzalo123.wordpress.com/2011/02/28/watermarks-in-our-images-with-php-and-mod_rewrite/

https://www.phpjabbers.com/put-watermark-on-images-using-php-php20.html

https://www.zubrag.com/scripts/watermark-image.php

https://911-need-code-help.blogspot.com/2008/11/watermark-your-images-with-another.html

https://weblantropia.blogspot.com/2008/03/image-resize-y-watermark-con-php-y-gd.html

I hope these are helpful.
regards.

Not sure, but NextGEN Gallery plugin, I think it uses the GD graphics library to do that.

I don’t know much more.
regards.