1. An image forming apparatus comprising: an image carrying member; a charging device that uniformly charges a surface of the image carrying member; an exposure device that applies light to the charged image carrying member to form an electrostatic latent image; a development device that applies a development bias voltage to a developer carrying member which carries a developer including at least a toner and that moves the toner from the developer carrying member to the electrostatic latent image to form a visible image; a control portion that controls an exposure amount in the exposure device and the development bias voltage; and a storage portion that stores an exposure condition and a development condition, wherein a resolution of image data can be switched to at least two types, a standard resolution and a high resolution higher than the standard resolution, and when the resolution of the image data is set at the high resolution, the control portion controls the exposure amount in the exposure device to perform thinning processing on the image.