Normally, your script show the GIF version of Pins (in thumbnails) ?
I don't see change...
Can you provide some test links?
Your script need update its @include
It Match for:https://www.pinterest.se/pin/460422761882460428/
But Not Match for:https://fr.pinterest.com/pin/560698222335084558/
// @include https://*.pinterest.com/*
// @include https://www.pinterest.com/*