Synthetic dust continuum images at 880 μm for three evolutionary stages of the protoplanetary disk model with three local pressure bumps at 30 au and 60 au in Sect. 4.3. Panel a: t=0.38 Myr, pre-cavity stage; Panel b: t=0.60 Myr, post-cavity stage when the photoevaporative cavity moves to 18 au; Panel c: t=0.80 Myr, when the photoevaporative cavity merges with the inner bump at 30 au. The blanks within the inner disks in Panels b) and c) correspond to the photoevaporative cavities.