set camera to image is not for that purpose, its for making an image from the camera's view. (Like taking a picture, with the image being analogous to the film.)
Here are two functions in DBPro for a simple 1st person and 3rd person camera. The target variable is a DBPro object in both functions.
function jzDoFirstPersonFixedCamera(camera as integer, target as integer)
position camera camera, object position x(target), ...
object position y(target), ...
object position z(target)
set camera to object orientation camera, target
endfunction
function jzDo3rdPersonFixedCamera(camera as integer, target as integer, ...
magnitude as float, angle as float, ...
height as float)
set camera to object orientation camera, target
pitch camera up camera, angle
position camera camera, object position x(target), ...
object position y(target) + height, ...
object position z(target)
set camera to object orientation camera, target
pitch camera down camera, angle
move camera camera, magnitude
endfunction
You can make a cube, for example, and hide it. Then, you use the method that code does to control the camera.
I'm not sure at all how to do that with an image, or sprite, however. Sorry.