tci_file_name = sensing_date+uid+'_TCI.png' bg_file_name = tci_file_name ov_file_name = source_file_name bg = Image.open(bg_file_name) ov = Image.open(ov_file_name) bg = bg.convert("RGBA") ov = ov.convert("RGBA") new_img = Image.blend(bg,ov,1) new_img2 = Image.blend(bg,new_img,0.4) new_img2.save(source_file_name,"PNG")