The role of this plugin is to help wordpress administrator(s) / website owners to control and block images with explicit (nude/porn) content.

It can be described as a background running process which is activated on every image upload and/or comment posting.

The plugin is highly customizable so, its scanning behavior can be changed according to your needs.

It has 3 scanning profiles:

1. Moderate nude images

Main features:

• Excluding administrator(s) from scanning
• Scanning sensitivity adjusting
• Email sending whenever a `nude` image is uploaded
• Save uploader detail (such as: name, email, IP, etc.)
• Saving a copy of uploaded image for further use ( in a separate folder )
• Comment scanning for < img > tags and automatic scanning
• Image size limitations, for excluding profile pictures / thumbnails from scanning
• Automatic update
• Friendly and easy to use Settings Panel
• Overall activity log to easily track your uploads
• Batch approval / deleting
• Very good performances
• Automatic update system

You can try a live exemplification of the plugin here

For more details about this plugin and about core algorithm, check this out

codecanyon-11493630-nude-image-blocker-wordpress-plugin.zip