Duplicated photos with different sizes on iPhone 14 when downloading to PC

Could it be, that you have set the camera to take the photos in the 16/9 aspect ratio? Then the camera will take the photo still in the original 4/3 aspect ratio, but create an additional version, cropped to 16/9. The camera is always taking the images in the aspect ratio of the sensor 4:3, and and then saving an additional cropped version. This way we can change the cropping, if need a larger height because the feet have been cut off or similar.

When you download the photo via USB, the original directly from the sensor will be downloaded as IMG_E0001.HEIC at 3024 x 4032 pixels and the cropped version will be downloaded as IMG_E0001.HEIC with 2268x4032 pixels (using Matti's example names).

You can test this by reverting the image to the original on your iPhone. Then only the uncropped original will be downloaded.

On the Mac Image Capture.app via USB transfers original image and movie. If image pixel data has been edited, then there is the original image IMG_0001.HEIC and the edited IMG_E0001.HEIC (both with original metadata), and image and movie IMG_0001.AAE adjustmentData sidecar files describing the edits (so the user can continue or cancel edits on the Mac's Photos.app).

AirDrop default (Options: include Location and Captions) transfers edited date, location and caption.

AirDrop "All Photos Data" option with "Save to Downloads" option (or "Open in Photos" in older versions like iPadOS 17.6 and macOS 14.6) transfers original image and movie. If image or movie pixel data has been edited, there is the original IMG_0001.* and the edited IMG_E0001.* (confusingly both with original metadata!), and image and movie IMG_0001.AAE sidecar files describing the edits.

I wonder what workflow yields same name files in your setup?

For all purposes the photos taken in 16:9 are edited photos, because the camera is cropping them and thus creating two image files, one with the original as recorded by the sensor and the cropped file in 16.9.

So you can revert this cropping and have only one file, if you open the image in edit mode and then tap the button with the curved red arrow to revert to the original.

I suggested this just as a test to check, if your duplicates are cropped versions created by the camera. But as long as you want the 16:9 format you have to keep the two files.

Just to let you know, even though you get two different files, 4x3, and 16x9 (with an E,) there aren't two files actually taking up space in the phone. The E file is created only for export. Keeping an edited picture doesn't take up any more space-- you just get two choices with exported files.

Check if the photos are in different quality