SiO maser images and sizes for sources with positive maser detection. The color-coded images are intensity-weighted velocity images with red receeding and blue approaching with respect to the systemic velocity. The images are the sum of the SiO ν = 2, J = 1−0 transition at 42.8 GHz and of the ν = 1, J = 1−0 transition at 43.1 GHz. Sizes are superimposed. Maser image resolutions andbeam orientations are given in white squares. The yellow disk is thestellar photosphere. The white dashed circle shows the condensation distance of Al₂O₃. The blue, green, and red circles are the mid-infrared sizes in the 7.80−9.30 μm (SiO), 9.37−11.50 μm (Al₂O₃ and H₂O vapor) and 11.55−13.26 μm (water vapor) bands. The purple ring features the SiO-fitted rings. The ring could not be directly fitted to the SiO data for V Mon and U Ari and lowest valuesare shown. For V Mon, only the ν = 1, J = 1−0 transition at 43.1 GHz has been detected and is represented.