Arches Simple Thumbnailer

thumbnailer.py

from PIL import Image
import filetype

class SimpleThumbnailer(ThumbnailGenerator):
    IMAGES = (
        'png', 'jpg', 'jpeg', 'jpe', 'gif', 'bmp', 'dib', 'dcx',
        'eps', 'ps', 'im', 'pcd', 'pcx', 'pbm', 'pbm', 'ppm',
        'psd', 'tif', 'tiff', 'xbm', 'xpm',
    )
    def make_thumbnail(self, inputfile_path, outputfile_path, **kwargs):
        """
        Args:
            inputfile_path: a path to a file on disk to create a thumbnail from
            outputfile_path: a path to a file on disk where the thumbnail will be written to
        
        Returns: 
            None
        """
        file_type = filetype.guess(inputfile_path)
        if file_type in IMAGES:
            image = Image.open(inputfile_path)
            image.thumbnail((300, 300))
            image.save(outputfile_path)

I tried to use this with 'GENERATE_THUMBNAILS_ON_DEMAND = False', but it broke my gunicorn (took too much CPU time).
A first attempt of a fix is:

from PIL import Image
from django.utils.translation import gettext_lazy as _

class SimpleThumbnailer:
    # without Django dependencies, as translations were breaking it
    
    def make_thumbnail(self, inputfile_path, outputfile_path, **kwargs):
        try:
            # image extensions
            image_extensions = ('.jpg', '.jpeg', '.png', '.gif', '.bmp')
            
            if not inputfile_path.lower().endswith(image_extensions):
                return False
                
            with Image.open(inputfile_path) as img:
                img.thumbnail((300, 300))
                if img.mode in ('RGBA', 'P'):
                    img = img.convert('RGB')
                img.save(outputfile_path)
            return True
            
        except Exception as e:
            print(_("Thumbnail generation failed: %s") % str(e))
            return False