Images - deleting and scaling

In Storyline, if I want to change the slide size, whether I choose to scale content or not, the image stays the same size. This is fine. But if I have a different image that fits the new slide size, when I replace the images, they are not at 100% scale. There needs to be either:

1. a default of 100% scale when images are replaced
2. an easy way to change the size/scale of all instances of the same image at once
3. an easy way to delete every instance of the same image at once (whether they are in use or not). 

Preferably all three. Having to go in and change every single image is frustrating and takes too much time.