Image transforms are used extensively in image processing to convert one image form into another form. These transforms are either point-operation transforms or neighborhood-operation transforms. Point-operation transforms can be classified as either injective transforms or non-injective transforms depending on the type of mathematical function applied to the image and the image characteristics. In this paper we present a novel techniq e that can identify if an image was processed by a point-operation transform and classify the transform as being either injective or non-injective. The mapping function of the transform is also recovered in the process. The technique is applicable to both linear and non-linear transforms. Tests are conducted on real images to show the validity of our technique.