Emission regions observed towards W Hya of the lines v₂ = 1, J_Ka, Kc = 8_8, 1 − 9_7, 2 and v₂ = 1, J_Ka, Kc = 8_8, 0 − 9_7, 3 of H₂O (sum of the two lines); v = 0, N_J = 13_25/2 with F = 12 − 12 and F = 13 − 13 of OH; and v = 1, J = 3 − 2 of CO. The white contours show the size of the stellar disk at the appropriate frequencies (measured from fits of a uniform-disk source to the observed visibilities; Vlemmings et al., in prep.), the colour map shows the integrated line intensity normalised to its peak value, and the dashed green contours show emission 3, 5, and 7 times above the root mean square noise of the given image. The dashed white circle shows the extent of the small region (see text). The grey and red ellipses show the restoring beam of the continuum and line images, respectively. For the images in band 7, the two beams are equal.