thumbnailer setup for displaying pictures + pixelart correctly (not blurred due to filtering) on gnome, ubuntu

pixelart-thumbnailer

#!/bin/bash
# put this in /usr/local/bin/
# must be executable

IMG_URI="$1"       # %i
THUMB_SIZE="$2"    # %s
THUMB_URI="$3"     # %o

IMAGE_SIZE=$(identify -format "%w %h" "$1")
PIX_SIZE=128       # Size to classify as pixel art. Picture must fit inside this box.

WIDTH=$(echo $IMAGE_SIZE | cut -d ' ' -f 1)
HEIGHT=$(echo $IMAGE_SIZE | cut -d ' ' -f 2)

# https://www.imagemagick.org/script/command-line-processing.php#geometry
if [ "$WIDTH" -le $PIX_SIZE ] && [ "$HEIGHT" -le $PIX_SIZE ]; then
    # Magnify the thumbnail, apply point filtering to avoid smooth, blurred previews
    /usr/bin/convert\
        -colorspace sRGB "$IMG_URI"[0]\
        -background transparent\
        -flatten\
        -filter Point\
        -thumbnail "${PIX_SIZE}"\
        -gravity center\
        -extent "${PIX_SIZE}"\
        png32:"$THUMB_URI"
else # this is the same thing as in /usr/share/thumbnailers/gdk-pixbuf-thumbnailer.thumbnailer
    /usr/bin/gdk-pixbuf-thumbnailer -s $THUMB_SIZE "$IMG_URI" "$THUMB_URI"
fi

pixelart.thumbnailer

# put this is /usr/share/thumbnailers/
# this file MUST supersede /usr/share/thumbnailers/gdk-pixbuf-thumbnailer.thumbnailer to work
# either delete or comment the content of ^that file. The MIME types are superset of that.
# possibly renaming it to be alphabetically earlier than gdk-... would also work, but I didn't test it and wouldn't rely on that
[Thumbnailer Entry]
TryExec=/usr/local/bin/pixelart-thumbnailer
Exec=pixelart-thumbnailer %i %s %o
MimeType=image/png;image/bmp;image/x-bmp;image/x-MS-bmp;image/gif;image/x-icon;image/x-ico;image/x-win-bitmap;image/vnd.microsoft.icon;application/ico;image/ico;image/icon;text/ico;application/x-navi-animation;image/jpeg;image/x-portable-anymap;image/x-portable-bitmap;image/x-portable-graymap;image/x-portable-pixmap;image/tiff;image/x-xpixmap;image/x-xbitmap;image/x-tga;image/x-icns;image/jp2;image/jpeg2000;image/jpx;image/x-quicktime;image/qtif;image/vnd.adobe.photoshop;image/x-photoshop;image/x-psd;application/psd;application/x-psd;image/webp;