saving image in ggplot & ggmap

i have saved an image using ggsave function which look as below

but i want to have output like this

       al1 <- get_map(location = c(lon = -86.304474, lat = 32.362563), zoom = 11, maptype = 'terrain')

      lon<--86.304474
      lat<-32.362563
      df<-data.frame(lon,lat)
      a+ggplot(df)
      ggmap(al1)+geom_point(data=df,aes(x=lon,y=lat),size=2)

i tried to removed x and y axis values but problem is that image have white background at the panel but i want only plot image.