fBm images with β = 2.5 and with resolutions of 250 × 250 pixels (top left), 500 × 500 pixels (top right), and 1000 × 1000 pixels (bottom left). The Δ-variance spectra for all three cases are compared in the bottom-right subpanel. All display a self-similar regime with an exponent of the power law of α = β − 2 (i.e., Eq. (4)). All maps are normalized by their own mean value, and the vertical offset between the three Δ-variance functions simply reflects the effect of this different normalization.