People with dementia (PWD) and their caregivers often develop depressive symptoms. Recent studies have shown that art therapies can improve mood among PWD and caregiver dyads. However, the exact effect remains unclear. We aim to assess the effect of a positive art intervention program on alleviating depressive symptoms in such dyads using a randomized controlled trial. A one-hour weekly program combining self-portrait photography and collage production was conducted for 8 dyads (PWD: n = 8; caregivers: n = 8) across four sessions (three photography and one collage session). The caregivers helped PWD to implement the tasks at every session. We measured current feelings (ranging from extreme unhappiness to extreme happiness) before and after every session using a face visual analogue scale (VAS). The results showed that no adverse events occurred during the intervention period. All participants were able to operate a camera and make a collage and were satisfied with the program. VAS scores significantly improved after the program: PWD (the 3rd session: p =0.500, the 4th: p = 0.058) and caregivers (the 3rd: p = 0.018, the 4th: p = 0.017). These findings suggest the program is feasible and can be used as a potential method to improve mood.