Depth image problem

Question

hi
i finished writing c# algorithm that is applied on a '24 bit depth' bitmap image that i called from file, and it was success; but when i apply the algorithm on a 32 bit depth image a break while running occur which is : " Value does not fall within the expected range".

what i have to do in order to apply my code on this type of image "32bit".
i think i have to do something after the 'image.fromfile', to make it acceptable by the rest of the code.
plz reply me your suggestion!