Here’s a 1st pass. Generated by GPT-5.3-Codex (OpenAI). The WebP thumbnailer is working as an addon. But ran out of free prompts for the AVIF thumbnailer. AVIF will follow when it resets.
Available for Gramps 6.0.x through Addon Manager using my curated GitHub repo:
https://raw.githubusercontent.com/emyoulation/CuratedGrampsPlugins/master/gramps60/
webp_thumb.gpr.py
#
# Gramps - a GTK+/GNOME based genealogy program
#
# Copyright (C) 2026 OpenAI (GPT-5.3-Codex)
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
#
"""
Gramps plugin registration for WebP thumbnailer plugin.
Author: Brian McCullough
Development: AI-assisted using OpenAI (GPT-5.3-Codex)
Date: April 2026
"""
from gramps.gen.const import GRAMPS_LOCALE as glocale
_ = glocale.translation.gettext
MODULE_VERSION = "6.0"
register(
THUMBNAILER,
id="webpthumb",
name=_("WebP Thumbnailer"),
description=_("Dedicated thumbnailer for WEBP images"),
version="0.1.3",
gramps_target_version=MODULE_VERSION,
status=EXPERIMENTAL,
order=START,
fname="webp_thumb.py",
thumbnailer="WebPThumb",
authors=["OpenAI (GPT-5.3-Codex)"],
authors_email=["https://openai.com"],
maintainers=["Brian McCullough"],
maintainers_email=["emyoulation@yahoo.com"],
requires_gi=[("GdkPixbuf", "2.0")],
help_url="https://gramps.discourse.group/t/webp-image-not-supported/8246/5",
)
webp_thumb.py
#
# Gramps - a GTK+/GNOME based genealogy program
#
# Copyright (C) 2026 OpenAI (GPT-5.3-Codex)
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
#
"""A dedicated thumbnailer addon for WEBP images."""
# -------------------------------------------------------------------------
#
# Standard python modules
#
# -------------------------------------------------------------------------
import logging
import importlib
import os
import shutil
import subprocess
import tempfile
# -------------------------------------------------------------------------
#
# GTK/Gnome modules
#
# -------------------------------------------------------------------------
import gi
gi.require_version("GdkPixbuf", "2.0")
from gi.repository import GdkPixbuf
# -------------------------------------------------------------------------
#
# Gramps modules
#
# -------------------------------------------------------------------------
from gramps.gen.const import THUMBSCALE, THUMBSCALE_LARGE, SIZE_LARGE
from gramps.gen.plug import Thumbnailer
# -------------------------------------------------------------------------
#
# Constants
#
# -------------------------------------------------------------------------
LOG = logging.getLogger(".thumbnail")
class WebPThumb(Thumbnailer):
"""Thumbnailer implementation for image/webp."""
MIME_TYPE = "image/webp"
def is_supported(self, mime_type):
"""Return True only for WEBP MIME."""
return mime_type == self.MIME_TYPE
def run(self, mime_type, src_file, dest_file, size, rectangle):
"""
Build a thumbnail by scaling a WEBP image and writing PNG output.
"""
detected_type = self._detect_content_type(src_file)
if detected_type is not None and detected_type != mime_type:
LOG.warning(
"MIME/content mismatch for thumbnail decode: mime=%s detected=%s file=%s",
mime_type,
detected_type,
src_file,
)
try:
pixbuf = GdkPixbuf.Pixbuf.new_from_file(src_file)
width = pixbuf.get_width()
height = pixbuf.get_height()
if rectangle is not None:
upper_x = min(rectangle[0], rectangle[2]) / 100.0
lower_x = max(rectangle[0], rectangle[2]) / 100.0
upper_y = min(rectangle[1], rectangle[3]) / 100.0
lower_y = max(rectangle[1], rectangle[3]) / 100.0
sub_x = int(upper_x * width)
sub_y = int(upper_y * height)
sub_width = int((lower_x - upper_x) * width)
sub_height = int((lower_y - upper_y) * height)
if sub_width > 0 and sub_height > 0:
pixbuf = pixbuf.new_subpixbuf(sub_x, sub_y, sub_width, sub_height)
width = sub_width
height = sub_height
thumbscale = THUMBSCALE_LARGE if size == SIZE_LARGE else THUMBSCALE
scale = thumbscale / float(max(width, height))
scaled_width = int(width * scale)
scaled_height = int(height * scale)
pixbuf = pixbuf.scale_simple(
scaled_width, scaled_height, GdkPixbuf.InterpType.BILINEAR
)
pixbuf.savev(dest_file, "png", "", "")
return True
except Exception as err:
LOG.warning("GdkPixbuf WEBP decode failed, trying Pillow fallback: %s",
str(err))
return self._run_with_pillow(src_file, dest_file, size, rectangle)
def _run_with_pillow(self, src_file, dest_file, size, rectangle):
"""
Fallback renderer using Pillow if GdkPixbuf cannot decode WEBP.
"""
pil_spec = importlib.util.find_spec("PIL.Image")
if pil_spec is None:
LOG.warning("Pillow fallback unavailable; PIL.Image not installed")
return False
Image = importlib.import_module("PIL.Image")
pil_features = importlib.import_module("PIL.features")
webp_codec_available = pil_features.check("webp")
LOG.warning(
"Pillow fallback diagnostic: WEBP codec available=%s, file=%s",
webp_codec_available,
src_file,
)
try:
image = Image.open(src_file)
width, height = image.size
if rectangle is not None:
upper_x = min(rectangle[0], rectangle[2]) / 100.0
lower_x = max(rectangle[0], rectangle[2]) / 100.0
upper_y = min(rectangle[1], rectangle[3]) / 100.0
lower_y = max(rectangle[1], rectangle[3]) / 100.0
left = int(upper_x * width)
top = int(upper_y * height)
right = int(lower_x * width)
bottom = int(lower_y * height)
if right > left and bottom > top:
image = image.crop((left, top, right, bottom))
width, height = image.size
thumbscale = THUMBSCALE_LARGE if size == SIZE_LARGE else THUMBSCALE
scale = thumbscale / float(max(width, height))
scaled_width = max(1, int(width * scale))
scaled_height = max(1, int(height * scale))
image = image.resize((scaled_width, scaled_height))
image.save(dest_file, format="PNG")
return True
except Exception as err:
LOG.warning("Pillow WEBP fallback failed: %s", str(err))
self._log_webp_signature(src_file)
return self._run_with_ffmpeg(src_file, dest_file, size, rectangle)
def _run_with_ffmpeg(self, src_file, dest_file, size, rectangle):
"""
Final fallback: use ffmpeg to decode the first frame, then scale as PNG.
"""
ffmpeg_path = shutil.which("ffmpeg")
if ffmpeg_path is None:
LOG.warning("ffmpeg fallback unavailable; ffmpeg executable not found")
return False
with tempfile.TemporaryDirectory(prefix="gramps_webp_thumb_") as temp_dir:
decoded_path = os.path.join(temp_dir, "decoded.png")
cmd = [
ffmpeg_path,
"-v", "error",
"-y",
"-i", src_file,
"-frames:v", "1",
decoded_path,
]
result = subprocess.run(cmd, capture_output=True, text=True, check=False)
if result.returncode != 0:
LOG.warning("ffmpeg WEBP fallback failed: %s", result.stderr.strip())
return False
try:
pixbuf = GdkPixbuf.Pixbuf.new_from_file(decoded_path)
width = pixbuf.get_width()
height = pixbuf.get_height()
if rectangle is not None:
upper_x = min(rectangle[0], rectangle[2]) / 100.0
lower_x = max(rectangle[0], rectangle[2]) / 100.0
upper_y = min(rectangle[1], rectangle[3]) / 100.0
lower_y = max(rectangle[1], rectangle[3]) / 100.0
sub_x = int(upper_x * width)
sub_y = int(upper_y * height)
sub_width = int((lower_x - upper_x) * width)
sub_height = int((lower_y - upper_y) * height)
if sub_width > 0 and sub_height > 0:
pixbuf = pixbuf.new_subpixbuf(sub_x, sub_y, sub_width, sub_height)
width = sub_width
height = sub_height
thumbscale = THUMBSCALE_LARGE if size == SIZE_LARGE else THUMBSCALE
scale = thumbscale / float(max(width, height))
scaled_width = max(1, int(width * scale))
scaled_height = max(1, int(height * scale))
pixbuf = pixbuf.scale_simple(
scaled_width, scaled_height, GdkPixbuf.InterpType.BILINEAR
)
pixbuf.savev(dest_file, "png", "", "")
LOG.warning("ffmpeg WEBP fallback succeeded for file=%s", src_file)
return True
except Exception as err:
LOG.warning("ffmpeg decode succeeded but PNG scaling failed: %s", str(err))
return False
def _log_webp_signature(self, src_file):
"""
Log WEBP signature diagnostics to help identify mislabeled/corrupt files.
"""
try:
with open(src_file, "rb") as file_handle:
header = file_handle.read(16)
has_riff = len(header) >= 12 and header[0:4] == b"RIFF"
has_webp = len(header) >= 12 and header[8:12] == b"WEBP"
has_avif_ftyp = len(header) >= 12 and header[4:8] == b"ftyp" and header[8:12] == b"avif"
LOG.warning(
"WEBP header diagnostic: riff=%s webp=%s avif_ftyp=%s header_hex=%s file=%s",
has_riff,
has_webp,
has_avif_ftyp,
header.hex(),
src_file,
)
if has_avif_ftyp:
LOG.warning(
"File appears to be AVIF data mislabeled as WEBP: %s",
src_file,
)
except Exception as err:
LOG.warning("WEBP header diagnostic failed: %s", str(err))
def _detect_content_type(self, src_file):
"""
Best-effort content signature check for WEBP/AVIF.
"""
try:
with open(src_file, "rb") as file_handle:
header = file_handle.read(16)
if len(header) >= 12 and header[0:4] == b"RIFF" and header[8:12] == b"WEBP":
return "image/webp"
if len(header) >= 12 and header[4:8] == b"ftyp" and header[8:12] in (b"avif", b"avis"):
return "image/avif"
except Exception as err:
LOG.warning("Content signature detection failed: %s", str(err))
return None
