Apple's USB-C to SD card reader (USB 2.0) adapter is compatible with the iPhone 15 Pro, which has a USB-C port for direct connection of external USB-C devices. To transfer photos from an SD card, simply connect the adapter to the iPhone 15 Pro via its USB-C port, then insert the SD card into the adapter. No additional accessories are required to transfer photos from a standard SD card.

However, it's important to note that this adapter supports USB 2.0, so transfer speeds will be slower compared with a USB 3.0 adapter. Also, the SD card must be a standard SD card; if you have a mini SD card, you'll need a mini SD to standard SD card adapter to insert it into this reader.

In a nutshell:
- Plug the USB-C to SD card reader adapter directly into the iPhone 15 Pro.
- Insert the SD card (with an adapter if it's a mini SD).
- The iPhone will automatically detect the photos and import them.
- No additional hardware required.