Answer:

1. they can never create a REAL image

2. they can never create an image larger than the object; and,

3. the image gets larger as the object gets closer

The image STARTS at infinitely small height. and located at the focal point, hen the object is at "infinity." Then, as the object approaches the surface of the mirror, the image does, too; and grows in size until -- when the object is right in front of the mirror -- the image is basically the same size as the object and "just inside" the surface of the mirror. This is because, when the object is that CLOSE, the convex mirror looks a lot like a plane mirror, which would just produce an equal-sized virtual image the same DISTANCE on the other side of the mirror surface from the object. The same thing is TRUE for an object right next to a concave mirror. That also produces an equal-sized virtual image right on the other side of the mirror, because, that close, the concave mirror looks basically like a plane mirror, as well.

So, for part b, I would say the ray diagram must be incorrect somehow, because of overriding principle 2.

When locating an image with a ray diagram, I usually rely on two chief rays:

1. A ray that comes in parallel to the optical axis, which then reflects off the mirror so that it looks like it come from the principal focal point, which is inside a convex mirror

2. A ray that reflects at the point where the optical axis intersects the mirror surface. That ray just reflects around the axis as it would off a plane mirror (so that its incident angle with respect to the axis is the same as its reflected angle with respect to the axis).