The option of changing the thumbnail size of the featured image size does not work in the post excerpts. Basically, changing the SETTINGS - FEATURED IMAGE SETTINGS - THUMBNAILS SIZE will only affect the "AUTO SELECTed IMAGES FROM POSTS" (i.e. the 1st image in a post"), but WILL NOT change the thumbnail size of the FEATURED IMAGES!
I would REALLY APPRECIATE if someone could suggest me a solution to this! (i.e. changing some setting in the Editor or whatever you can come up with!)