Phone was fine yesterday, took lots of photos which went into Gallery as well as Google Photos, and lots were in the Gallery anyway. Today there are only four old photos in the Gallery. How can I restore them, what has happened? I am not technical at all. It is a Samsung A40. Luckily they are all still in Google Photos although I had a message on my phone yesterday saying I had used half of my allowance for Google Photos (can’t remember the wording). Another problem, I can send photos from Google Photos to WhatsApp, but not videos. Just get a black screen and a circle going round and round. All was fine yesterday, with this as well. Thanks all. Easy answers please!!
You've probably got Google set to remove the backed up photos. This doesn't stop you viewing then normally as Google downloads the thumbnails on demand. Judging by your other symptoms, I diagnose a cr*ppy internet connection.
Once you sort out your internet connection problem, the pictures will reappear in Photos on your phone. If you tap one to view it, you can then tap the menu at top right and choose download.