YouTube 'daily custom thumbnail limit reached': retry in 24 hours

YouTube limits how many custom thumbnails a channel can upload each day, and the limit varies by region and channel history. When you see the error 'daily custom thumbnail limit reached', try again in 24 hours, so a batch loop should stop and reschedule instead of retrying.

What does the page say?

The limit is not a fixed published number.

How should a batch behave?

Generate or extract thumbnails ahead of time, and upload only the number the channel accepts. This function turns a queue into a schedule when you know your own allowance, which you must discover for your channel.

def schedule(queue, per_day):
    return [queue[i:i + per_day] for i in range(0, len(queue), per_day)]

days = schedule(["t%02d" % n for n in range(1, 8)], per_day=3)
for d, items in enumerate(days, start=1):
    print("day", d, items)

Does Sume re-render on retry?

No. Sume jobs take an Idempotency-Key, and finished results are durable URLs, so a rescheduled upload reuses the same image. Re-render only if you change the creative.