Theme: MH Purity. Feature image resizing problem

Hi,

The theme was cropping the featured images on my posts to fit the horizontal size of 650 to 276. I want to reduce the featured image size proportionally (without cropping) to fit the maximum width of 650. I changed the 2nd line below from “true” to “false” and was able to achieve the size I wanted. I regenerated my thumbnails.

add_image_size(‘slider’, 990, 422, true);
add_image_size(‘content’, 650, 276, false);
add_image_size(‘featured’, 310, 174, true);
add_image_size(‘cp_small’, 80, 60, true);

My problem is that it is now upsizing a thumbnail to reach the 650 width as opposed to downsizing the original upload. The result is a very low resolution image as the featured image. How can I fix?

Any help would be appreciated!