Carlos Minatti

Delete Original Image is a WordPress plugin to delete the the original image file uploaded.
The problem that solves, is that the original image file is usually huge (can be >6MB if it is a photograph) and it is never published on the pages, so there is no need to keep it on your server, and it it a must to delete it, if you have limited storage space and you are uploading tons of pictures.
The plugin gives you the option to enable/disable this, to be done automatically when you upload an image.
And/or you can do it in bulk for all your previously uploaded images.
Specifically, this plugin copy the ‘large’ image ( i.e: your-pic-1038×576.jpg ) to the original file path ( i.e.: your-pic.jpg ).
Nothing should brake, all other plugins should keep working, but you need to know that the original image is no longer available on your site, so please do a backup if you think you may need the original images in the future.

Delete Original Image

This plugin allows you to automatically delete the original image after upload, or do it in bulk for old images.

Jeremy Ross

Field to select registered image sizes within the WordPress dashboard.
<h3>Compatibility</h3>
This ACF field type is compatible with: 
* ACF 5
<h3>How to Use</h3>
Once activated, this plugin will create a Image Size field type in ACF. This field type will list all registered field types as a drop down within the field group.
To use this field within your custom templates you will use the following code:
<pre><code>$my_image_id = get_field('my_image_id'); // ACF Image return type set to ID for this demo
$my_image_size = get_field('my_image_size'); // The selected image size (eg. large)

echo wp_get_attachment_image( $my_image_id, $my_image_size ); // Output the image based on the ID, and the Image Size selected.
</code></pre>

Advanced Custom Fields: Image Size Select Field

Field to select registered image sizes within the WordPress dashboard.

Delete Original Image vs Advanced Custom Fields: Image Size Select Field