If the object is at the infinity, the image is formed at the focus. If the object is at the focus, the image is formed at the infinity. And the spherical mirrors produce virtual images only when the image is formed behind the mirror.

When the object is at infinity in concave lens?

Concave Lenses

When an object is placed at infinity, a virtual image is formed at the focus. The size of the image is much smaller than that of the object.

When the object is located at infinity the image is located at?

The image is real light rays actually focus at the image location). As the object moves towards the mirror the image location moves further away from the mirror and the image size grows (but the image is still inverted). When the object is that the focal point, the image is at infinity.