1. An image forming apparatus, comprising: a memory device that stores a set of instructions; and at least one processor that executes the instructions to: determine whether or not a scaling degree in a processing of inputted image data exceeds a predetermined threshold, and in a case where it is determined that the scaling degree of the inputted image data does not exceed the predetermined threshold, execute processing for scaling the inputted image and then execute first prediction processing that predicts an amount of applied toner using image data after scaling, and in a case where it is determined that the scaling degree of the inputted image data exceeds the predetermined threshold, execute second prediction processing that predicts the amount of applied toner using the inputted image data prior to scaling and then execute scaling processing after executing the second prediction processing.