iPhone 15 is not captured photos in full 24MP size

Good Evening.

The iPhone 15 , as i know, have a 24MP main camera..

Why are the pictures are taking with the main and telephoto lens, having 18MP(for the main) and 9MP (front ) as result, and not the full quality? I have selected the most compatible in the setting and 24MP photo mode , but still photos are captured in 18mp size in IPhone 15 .. Please let me know any other setting should be enabled/ disabled in the Camera setting to bring 24MP size …

waiting your valuable feedback,

Thanks in advance!

Pradeep Rao