How to regenerate thumbnails when they’re stored on S3

I have a WordPress site that uses the WPRO (WordPress Read Only) plugin to host all media files on Amazon S3. I’ve changed the thumbnail and image sizes in my custom theme, and uploading new images to the media library uses the new sizes. However, when I try to regenerate all thumbnails using “Regenerate Thumbnails,” it doesn’t work, often complaining that the original cannot be found.

How can I force the regenerate thumbnails plugin to use the original image on S3 to recreate the thumbnails for existing images?

You can”t in any automatic way. originals should always be stored on the wordpress server, never remove them.

If you still have the originals anywhere then the only way is to manually place them at the right location in which they wnere