First off, what a great plugin you've built sewpafly! It's perfect with themes like Arras, which is the theme that I'm using right now. However, I plan to change my website theme to a premium theme from WPZOOM, but unfortunately it looks like those premium themes are not compatible with your plugin.
The premium themes have their own code which shrinks and centers the images to fit thumbnails of different sizes and aspect ratio and it doesn't give you the level of control your plugin gives to a user. So is it possible to change the codes in the themes and perhaps make it compatible with your plugin? Thanks for your time sewpafly.