Since 1.5.4, I believe, Image Watermark plugin stopped working on my website with WordPress 4.5.1. Before it worked just fine.
Unfortunately, I updated it now on version 1.5.5 and it still doesn’t work with Manual Watermarking in Media Library. I mention that I didn’t change any setting and I removed the watermark image and added a new one, but the problem persists.
I’ve updated the plugin to 1.5.6. It watermarks images, but the watermark isn’t showing unless I click them (for example, images in this article: https://itutorial.ro/2016/05/dosar-implicit-finder/ ). I mention that I have checked every image size in the plugin settings and the watermarking worked in version 1.5.5 beta that you’ve sent to me.