--- a/docs/examples/filter_image_pixels.py	2025-05-26 19:26:56.000000000 +0800
+++ b/docs/examples/filter_image_pixels.py	2025-05-27 14:03:08.062545039 +0800
@@ -6,13 +6,17 @@
 from astropy.wcs import WCS as WCS
 from mocpy import MOC
 
-# load 2MASS cutout covering the galactic plane
-hdu = fits.open(
-    "http://alasky.u-strasbg.fr/hips-image-services/hips2fits?hips=CDS%2FP%2F2MASS%2FK&width=1200&height=700&fov=30&projection=TAN&coordsys=galactic&rotation_angle=0.0&object=gal%20center&format=fits",
-)
+# load 2MASS cutout covering the galactic plane. Use local fits if no network while doc building.
+try:
+    hdu = fits.open(
+        "http://alasky.u-strasbg.fr/hips-image-services/hips2fits?hips=CDS%2FP%2F2MASS%2FK&width=1200&height=700&fov=30&projection=TAN&coordsys=galactic&rotation_angle=0.0&object=gal%20center&format=fits",
+    )
+except Exception:
+    hdu = fits.open('cutout-CDS_P_2MASS_K.fits')
 
-# load Spitzer MOC
-moc = MOC.from_fits("http://skies.esac.esa.int/Spitzer/IRAC1_bright_ISM/Moc.fits")
+# load Spitzer MOC. Use local fits if no network while doc building.
+try: moc = MOC.from_fits("http://skies.esac.esa.int/Spitzer/IRAC1_bright_ISM/Moc.fits")
+except Exception: moc = MOC.from_fits('Moc.fits')
 
 # create WCS from 2MASS image header
 twomass_wcs = WCS(header=hdu[0].header)