Resize uploaded original images to a minimum automatically

Question

Facebook recommends to use for sharing images with a minimum size of 600 x 315 pixels and an 1.91:1 aspect ratio. Is there a way to automatically resize down original images uploaded to Wordpress to a size as close as possible to the recommended? I tried some plugins for resizing, but if images will not have the recommended 1.91:1 aspect ratio, one of the minimum sizes (width or height) will be smaller than recommended, because these plugins have a maximum size setting and not a minimum size setting. For example, if an original image have a size of 960 x 720 pixels, after resizing with a such plugin it have 420 x 315 pixels, so only the height is respected. In my WP installation posts are shared to FB with original images as a featured image, this is why I need a solution here. Maybe other scenarios can be used for this. Any help?

P.S. I can't set minimal dimensions for uploaded images because my posts are created by importing collected Facebook events which already have attached images of different sizes.

Answer 1

From purely WordPress point of view you want add_image_size() with a "hard" crop mode. That will ensure that any significantly large image will be sized to fit into those dimensions exactly, cropping some parts if necessary.

The problem is usually that WP won’t upsize small images to fit, as far as I remember. It is most definitely possible to implement custom sizing logic, but it's not something straightforward really.

In my opinion hard crop size is reasonable low hanging solution here. Anything that it can't handle probably requires human attention for decent result anyway.