Use JPEG instead of PNG on thumbnails

CHANGES.rst

@@ -8,6 +8,7 @@ Changes
 - Swipe support
 - More space for images
 - Restructure repository
+- Use JPEG instead of PNG for thumbnails
 
 1.0.3 (*2021-07-13*)
 ~~~~~~~~~~~~~~~~~~~~

README.rst

@@ -49,7 +49,9 @@ same galleria name. In this case, node level options
 must be defined only once.
 
 Thumbnail size is in "WIDTHxHEIGHT" format, resulting
-image keeps ratio.
+image keeps ratio. Be careful with tumbnail size, the
+browser loads all thumbnails of a gallery when loading
+the page. It can take some time with really big galleries.
 
 The first image of a gallery is displayed if javascript
 is not available on the browser.

__init__.py

@@ -11,8 +11,8 @@ from sphinx.environment import BuildEnvironment
 from sphinx.util.osutil import ensuredir, copyfile
 from PIL import Image
 
-from . import directive
-from . import collector
+from sphinx_galleria import directive
+from sphinx_galleria import collector
 
 
 with open(os.path.join(
@@ -43,7 +43,7 @@ def copy_images_files(app: Sphinx, env: BuildEnvironment) -> None:
             thumbsize = basename.split('-')[-1].split('x')
             thumbsize = [int(size) for size in thumbsize]
             original = '.'.join(basename.split('.')[:-1]) + ext
-            dest = basename + '.png'
+            dest = basename + '.jpg'
             ensuredir(os.path.dirname(dest))
 
             with Image.open(original) as im:
@@ -68,7 +68,7 @@ def copy_images_files(app: Sphinx, env: BuildEnvironment) -> None:
                         (im.size[1]+thumbsize[0]*im.size[1]/thumbsize[0])//2,
                     ))
 
-                out.save(dest, "PNG")
+                out.save(dest, "JPEG", quality=90)
 
 
 def install_static_files(app: Sphinx, env: BuildEnvironment) -> None:

collector.py

@@ -10,14 +10,15 @@ import glob
 import logging
 from copy import copy
 from typing import Set
-from sphinx.environment.collectors import EnvironmentCollector
+
 from docutils import nodes
+from sphinx.environment.collectors import EnvironmentCollector
 from sphinx.application import Sphinx
 from sphinx.environment import BuildEnvironment
 from sphinx.util import FilenameUniqDict
 from sphinx.locale import __
 
-from .directive import galleria
+from sphinx_galleria.directive import galleria
 
 logger = logging.getLogger(__name__)
 
@@ -86,7 +87,7 @@ class GalleriaCollector(EnvironmentCollector):
                     basename, ext = os.path.splitext(image_path)
                     thumb_path = basename + ".thumb-" + thumbsize + ext
                     thumb_path_cropped = basename + ".thumb-" + thumbsize
-                    thumb_path_cropped += '.png'
+                    thumb_path_cropped += '.jpg'
                     if ext.lower() in ('.svg', '.svgz'):
                         thumb_path_cropped = image_path
                         thumb_path = image_path
@@ -109,7 +110,7 @@ class GalleriaCollector(EnvironmentCollector):
                             app.srcdir,
                             image_path), os.R_OK):
                         logger.warning(
-                            __('image file not readable %s') %
+                            __('image file not readable %s'),
                             image_path)
 
                     app.env.galleria.add_file(docname, image_path)