<div>
    <input type="file" @change="previewImage" accept="image/*" />
</div>

 previewImage(event) {
        let q = event.target.files[0]
        const storageRef = firebase
          .storage()
          .ref('name папки из стораджа' + `${q.name}`)
          .put(q)
        storageRef.on(
          `state_changed`,
          snapshot => { },
         (error) => {
               console.log(error.message)
          },
          () => {
            storageRef.snapshot.ref.getDownloadURL().then(url => {
              this.picture.push(url)
            })
          }
        )
      },