我想你说的“结合两幅图像”，是指把它们连接起来，就像把它们缝合成一幅

from pathlib import Path
from PIL import Image

src_parent_dir = Path("parent/folder/of/folder1/2/3/and/4")
dest_dir = Path("folder/to/result/images")
img_name2path = {}  # look up buffer

for child in src_parent_dir.glob("*/*.png"):  # assume all images ends with png
    img_name = child.name
    src0_path = img_name2path.get(img_name)
    if src0_path is None:  # store first image, look for second image
        img_name2path[img_name] = child
    else:  # first image found
        src0 = Image.open(src0_path)
        src1 = Image.open(child)
        dst = Image.new("RGBA", (src0.width + src1.width,
                        max(src0.height, src1.height)))
        dst.paste(src0, (0, 0))
        dst.paste(src1, (src0.width, 0))
        # this puts them side by side horizontally
        '''
        dst = Image.new("RGBA", (max(src0.width, src1.width)
                        src0.height + src1.height)))
        dst.paste(src0, (0, 0))
        dst.paste(src1, (0, src0.height))
        # use this to stack them vertically instead
        '''
        name = src0_path.stem
        suffix0 = src0_path.parent.name  # used to make dest file name
        suffix1 = child.parent.name  # used to make dest file name
        dst.save(Path(dest_dir, f"{name}_{suffix0}_{suffix1}.png"))
        # result image is named like a_1_folder1_folder2.png
        img_name2path[child.name] = None  # reset buffer
# Finally, deal with leftover single images
for img_name, src_path in img_name2path.items():
    if src_path is None:  # no leftover
        continue
    src = Image.open(src_path)
    dst = Image.new("RGBA", (src.width, src.height))
    dst.paste(src, (0, 0))
    dst.save(Path(dest_dir, 
                  f"{src_path.stem}_{src_path.parent.name}.png"))