Top: simulated stellar images of different spectral types, as seen by the Euclid VIS imager, shown with a logarithmic flux scale. Bottom: differences between pairs of these images, shown with a linear flux scale. White is positive and black is negative. Note that for demonstration purposes, this illustration is highly idealised: the above stellar images do not contain any noise, and the profiles are centred at exactly the same position with respect to the pixel grid.