uploads – Alter the image, before save, of a particular image size

Is there a way/filter to edit the image (as in the image file itself) before it is saved, on a per image size basis?

Particularly, I want to have a version of an image that I’ll apply a blur effect to. I’ll call my custom image size, say, `500x500_blurred’ with:

add_image_size('500x500_blurred', 500, 500, true);

Now, on adding a new image, I’d like to alter the 500x500_blurred version before it is saved, applying some manipulations to just that image, so that the original image and all other size versions do not get the same manipulations.