A little more information might help:
- By "gallery," do you mean the Library in the Photos app?
- Are you really using iOS14?
- Are you using iCloud Photos to synchronize your devices? If so
- …Do you have “Optimize Storage” checked in Photos’ Settings
- …Do you see all your iPhone pictures at iCloud.com?
- …Have you checked to see if the Apple Account is really really the same on the Mac and on the iPhone and at iCloud.com?
- …Do you have more than 10% free storage on your iCloud account?
- What is your storage on this iPhone? At Settings>General>iPhone Storage, my phone says 50.5 GB of 128 GB used. What does yours say? Do you have more than 10% free storage on your iPhone?
- Has this problem always existed, or did it just start? Can you think of anything that changed that might affect your device?
- Are you meaning that when you take a picture you can't find it?
Let us know details so we can help…