"FileNotFoundError: [Errno 2] No such file or directory:" despite using full path

Just wondering if someone might be able to point me in the right direction as I’m at complete loss of what’s happening (I’m a beginner so sorry if this is blaringly obvious!).

I’m writing some code to create a photomosaic. It requires resizing photos from a database and then concating images together to create a bigger picture.

The relevant code is as follows:

def resize(self):
        path = "C:/Users/chloe/Desktop/Python_Stuffs/Robert_Heaton/landscape_images"
        dirs = os.listdir(path)
        new_path = Path(path, 'resized_pics')
        new_path.mkdir(parents=True, exist_ok=True)
        #etc.
        
 def concat_rows(self):
        path = "C:/Users/chloe/Desktop/Python_Stuffs/Robert_Heaton"
        new_path_concat = Path(path, 'photomosaic_images_' + im_name)
        new_path_concat.mkdir(parents=True, exist_ok=True)
        counter = 0
        for row in self.match_pixel_img:
            im1_path = os.path.join(self.new_path,row.pop(0))
            os.chdir(self.new_path)
            im1 = Image.open(im1_path)
            #etc.
 

In the function resize I create a new directory with the new resized pictures in, and then in concat_rows I take the resized images from the new directory and concat them. However, I’m getting this error:

    File "C:UserschloeDesktopPython_StuffsRobert_Heatonphotomosaic.py", line 95, in concat_rows
    im1 = Image.open(im1_path)

    File "C:Userschloeanaconda3libsite-packagesPILImage.py", line 2878, in open
    fp = builtins.open(filename, "rb")

    FileNotFoundError: [Errno 2] No such file or directory: 
    'C:\Users\chloe\Desktop\Python_Stuffs\Robert_Heaton\landscape_images\resized_pics\'

even though this is the directory I created in resize and I can SEE the directory in my files at that exact location. I’m using the fullpath so I’m really not sure what is wrong. Furthermore, when I run the code a second time it works fine so maybe it’s something to do with the way Python reads lines?

If anyone could shed some light I’d be really grateful!