How can I make the avatar appear in large format?

const Discord = require('discord.js');
 
module.exports = {
    name: 'avatar',
    description: 'returns a users avatar',
    execute(message, args){
        const { prefix, token } = require ('../config.json');
        const embed = new Discord.MessageEmbed()
 
        if(!message.mentions.users.first()){
            embed.setTitle(`:camera_with_flash:Avatar de: @${user.username}`)
            embed.setThumbnail(message.author.displayAvatarURL())
            embed.setDescription(`Clique aqui para baixar o avatar.`)
            embed.setColor('fffff1')
            embed.setFooter(".")
            return message.channel.send(embed)
        }else{
            const user = message.mentions.users.first()
            embed.setTitle(`:camera_with_flash:Avatar de: @${user.username}`)
            embed.setThumbnail(user.displayAvatarURL())
            embed.setDescription(`Clique aqui para baixar o avatar.`)
            embed.setColor('fffff1')
            embed.setFooter(".")
            return message.channel.send(embed)
        }
    }
}

I’m new to all this, sorry for my stupidity :c is my first discord bot! when I give the command !avatar on discord, the avatar comes out very small on the right of the embed

Answer

Thumbnails are small. You would need to place the avatar in .setImage() then have it set to scale up to 256 in size

.setImage(user.avatarURL({ format: 'png', dynamic: false, size: 256 }))

This will ensure the image reaches a big size. Just keep in mind that some avatars might be low resolution, and can seem over blown if at a larger size.