The situation is this: I'm using Video Thumbnails plugin to automatically get and set youtube/vimeo thumbnails as post featured image. The problem is that default youtube/vimeo thumbnail sizes are just a bit smaller than my theme main content width.
So what I need is to scale them up. If I go to the Media Library, I can edit each image manually, then set my exact width and WordPress scales it up just right (I dont mind that the quality is a bit worse). So is there a way that WP would do that automatically each time an image is uploaded?
This is my defined image size: add_image_size('post-full', 688, 320, true);
Vimeo thumb size is 640x320.