Different Thumbnail Sizes with Face Detection

It’s always a good practice to do a backup before you try a plugin that process your media library, in case anything goes wrong.

1. The plugin uses a 3rd party program (Face detection algorithm by Maurice Svay) to do the face detection. It can detect most a face from most of images with simple obvious faces. The cover image you gave, it can’t detect.

You can try your image this way to see if your image works first.
1.1 Upload your image at https://nvigen.com/fd.html, e.g. file name is ‘face3.jpg’
1.2 run https://nvigen.com/fd.php?image=wp-content/uploads/face3.jpg

If it can detect your image. You can install the plugin, run a cleanup. That’s all you need to do. It will clear the existing custom sized thumbnails (i.e. excluding system default). I assume yours are custom sized. Then when a new thumbnail is needed, it will be generated on demand, triggering the face detection.

2. The plugin says “AST helps remove these unused thumbnails and stop them from being generated when an image is uploaded.” It means once the plugin is installed, the custom sized thumbnails won’t be generated, until a page that shows the thumbnail is loaded.

3. It has no conflict with with CDN. It more depends how your CDN sync with the server, the media library specifically. The plugin operates on media library. If you run a clean up, it deletes all the custom sized thumbnails, and create one and store it in the media library when it’s requested.

Hi qiuliu,

Thanks for your very useful reply.

Regarding the custom images which are created by my theme here is the code from functions.php

add_image_size( ‘single-post’, 685, 336, true );
add_image_size( ‘full-width-single-post’, 1046, 512, true );
add_image_size( ‘trending-thumb’, 300, 147, true );
add_image_size( ‘section-large-thumb’, 486, 238, true );
add_image_size( ‘section-medium-thumb’, 300, 147, true );
add_image_size( ‘widget-thumb’, 345, 169, true );
add_image_size( ‘home-single-feat’, 560, 275, true );
add_image_size( ‘home-what-new’, 250, 123, true );
add_image_size( ‘home-trending-thumb’, 210, 103, true );
add_image_size( ‘sidebar-thumb’, 265, 130, true );

So, if I install your plugin, I can see these will not be created. However, what I need to know is if, for example, my theme needs to display home-trending-thumb, or sidebar-thumb etc.

How does this work with your plugin?

Please advise.
Thanks
Indy

My understanding is the thumbnails you need to display will be generated when they/the pages are displayed. It’s supposed to work this way but you won’t know until you test it. Do you have a dev/staging site to test it? Or you backup your media library first in case things don’t work.

Hi,

Thanks for your reply. Yes, we will test it on a test server.

So, the three images you generate – will they be used correctly by srcset i.e. smallest size which is a good fit for the device?

Please advise.

Thanks
Indy

It’s supposed to. The plugin doesn’t mind the size details.

Your theme register with WordPress what custom sizes it will create (to be used later). The plugin generates whatever specific size when the system (WordPress and your theme) loads it. The system will tell what exact size to create.

You can check in your media library after loading a page with a specific thumbnail to make sure it’s created.

If you suspect things don’t work, you can turn on debug log. I believe the plugin logs what it has done.

Btw, can I remove fd.html and fd.php? I see it works on all but one image.

• This reply was modified 3 years, 7 months ago by qiuliu.

Hi,

Thanks for your fast and useful responses.

Yes, you can remove fd.html and fd.php. Thank you.

It does work well apart from that one image.

I will set-up a test server and then test it out fully.

Thanks for your help.

Keep up the good work.

Regards,
Indi