Photos not displaying in full screen on iMac with Sonoma 14.7.2

I am using Sonoma 14.7.2 on my iMac. When I open photos the pictures are all there in the small version, if I double click them to go to full screen it goes black with no pictures, the thumb nails are at the bottom. If I slide side to side across the mouse the next picture comes across the screen but when I let go of the mouse it disappears. Has anyone any ideas please. PS Videos work OK.

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