An object AB is placed parallel and close to the optical axis between focus f and center of curvature C of a coverging mirror of focal length f as shown in the figure. Then 

 

Objects are between F and C. As a point object moves between C and F, images moves between C and $\infty$ . Since A is farther than B,
image of A will be closer. A and B have same height but their images will have different height due to difference in magnifications. Hence, image of AB will be inclined.
 For a concave mirror $magnification= \frac{-v}{f}+1$, So the image formed by AB will be straight line.