How to crop first, then resize?

The way resizing and cropping works in add_image_size is it resizes the image first, and then crops the image. Is there some way to crop to a desired size first, and then resize?

For example, say I have full images of logos that are all 1000×1000 px but the logos themselves only takes up the middle 600×600 of the images. I’d like my thumbnails of those images to show just the logos, so they should first be cropped to 600×600 first and then resized to the thumbnail size (eg., 100×100).

How would I go about doing something like that? Thanks for any help!