Update extension library images

Most images from TurboWarp/extensions#204
Closes TurboWarp/extensions#259

src/lib/libraries/extensions/custom/README.md

@@ -0,0 +1,28 @@
+# Image attribution
+
+## custom.svg
+
+{ } characters from https://github.com/jesseweed/seti-ui/blob/master/icons/json.svg under the MIT License:
+
+```
+Copyright (c) 2014 Jesse Weed
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+```

src/lib/libraries/extensions/gallery/README.md

@@ -1,12 +1,23 @@
-# Image Attribution
+# Image attribution
 
 Most of these images are adapted from: https://github.com/TurboWarp/extensions/tree/master/images
 
-## stretch.svg
-The dango is from [Twemoji](https://twemoji.twitter.com/) and is licensed under [CC-BY 4.0](https://creativecommons.org/licenses/by/4.0/).
+## gallery.svg
+ - Created by @True-Fantom in https://github.com/TurboWarp/extensions/issues/204
 
-## gamepad.svg
-Created by @DNin01 in https://github.com/TurboWarp/extensions/issues/90#issuecomment-1374365379. The gamepad art is adapted from [DNin01/icons](https://github.com/DNin01/icons) and is licensed under [CC-BY 4.0](https://creativecommons.org/licenses/by/4.0/).
+## stretch.svg
+ - Created by @True-Fantom in https://github.com/TurboWarp/extensions/issues/204
+ - Arrow icon from https://icon-icons.com/ru/%D0%B7%D0%BD%D0%B0%D1%87%D0%BE%D0%BA/%D0%A0%D0%B0%D0%B7%D0%BC%D0%B5%D1%80-%D1%81%D1%82%D1%80%D0%B5%D0%BB%D0%BA%D0%B8/83819 under CC-BY 4.0
+ - Dango icon from Twemoji under CC-BY 4.0
+ - Background is from https://haikei.app/
 
 ## cursor.svg
-The cursors based on the [Adwaita icon theme](https://gitlab.gnome.org/30butlerj/adwaita-icon-theme/-/tree/master/Adwaita/cursors) created by the GNOME project licensed under [CC-BY-SA 3.0](https://creativecommons.org/licenses/by-sa/3.0/) or [GNU GPLv3](https://www.gnu.org/licenses/gpl-3.0.en.html). We use SVG versions from https://github.com/manu-mannattil/adwaita-cursors.
+ - Created by @True-Fantom in https://github.com/TurboWarp/extensions/issues/204
+ - Background is from https://app.haikei.app/
+ - One cursor from https://commons.wikimedia.org/wiki/File:%D0%9A%D1%83%D1%80%D1%81%D0%BE%D1%80_%22%D0%97%D0%B0%D0%BD%D1%8F%D1%82%22.png under CC-BY-SA 4.0
+ - Two other cursors from https://commons.wikimedia.org/wiki/File:Mouse-cursor-hand-pointer.svg under CC-BY 2.5
+
+## gamepad.svg
+ - Created by @True-Fantom in https://github.com/TurboWarp/extensions/issues/204
+ - Gamepad icon from https://icon-icons.com/icon/appliances-console-controller-dualshock-gamepad-games-videogame/106553 under CC-BY 4.0
+ - Background from https://app.haikei.app/