batches: use the minimum possible goroutines to fetch images
Created by: LawnGnome
This was spotted by @eseliger in the review for #647 — if total < parallelism
, there's no real need to spawn extra goroutines, so let's not.
Created by: LawnGnome
This was spotted by @eseliger in the review for #647 — if total < parallelism
, there's no real need to spawn extra goroutines, so let's not.