Smartphone - Can I send multiple photos at once?

You can send up to 10 photos at a time on both Android and iOS. There is however no restrictions on how many recipients you want to send these photos to at the same time.

If you wish to transfer larger amounts of photos at the same time to a photo frame, you can import photos with a SD card.
Learn more about how to import photos with SD-card: Transfer photos from a PC to a photo frame