Take the following optical arrange for a concave mirror:
Where the letters stand for Object, Image, Focus, Center
For it, we can use the equation below to calculate image distance formation:
where $x$ stands for distance to the mirror, $o$ for object $i$ for image.
Do we need to be exactly on the beams intersection ($x_i$) to see the image?
I'm not very familiar with curve mirrors, but it doesn't make sense in my head, as objects can be seen with us standing on different positions.