Sticker gets sent as an image file

[xypnox]

The example from the readme for sending a sticker at a URL sends the sticker as an image file on both desktop and phone.

The relevant code:

bot.on('sticker', (msg) => {
    return msg.reply.sticker('http://i.imgur.com/VRYdhuD.png', { asReply: true });
});

Removing asReply resulted in the same messages.

Screenshot (first with asReply, second without):

PS: Please ignore the first sticker :|

[ghost]

As mentioned in the README, sendSticker seems only to work with .webp files

Use this method to send .webp stickers.

The official Telegram docs also only mention .webp files

sendSticker
Use this method to send static .WEBP or animated .TGS stickers. On success, the sent Message is returned.