Hello, I can't transfer photos to my phone... the app snap bridge works fine. but the photos I've shorted today are marked by a yellow cross and it doesn't allow me to transfer them, Thank you!
Unfamiliar with Snapbridge, but I do know that it cannot transmit Raw (NEF) files. If you shot Raw you must convert to JPG (this can be done in camera, as all Raw processing generates a new JPG file). If it's worked before but just won't do those images, my guess is that they're not in a permissible format.
If you do conversions from NEF in the camera, the camera will generate a new JPG with the same file number, but it will not alter the existing NEF at all. If you want, you can go back, do another conversion of the same file with different size or other processing, and yet another copy will be made. The camera never over-writes or deletes a picture unless you manually do so with the trash can button.
This is true, by the way, also for post processing JPG files in the camera. Every time you make a new change, that change is saved in a new file without erasing the old one.