Image Width (Exif Image Width / Pixel X Dimension)

Width of the image in pixels, as recorded in the EXIF.

EXIF tag ID: 0xA002
Group: Image
Example: 4032 · 6016 · 8064
Editable in EXIF Viewer: No (fixed by the image data)

What iPhone writes

4032 for 12 MP, 8064 for 48 MP ProRAW/HEIF Max.

What dedicated cameras write

Matches the sensor output size for the chosen quality.

How to view Image Width (Exif Image Width / Pixel X Dimension) on iPhone

Open the photo in Photos, tap Share, then View EXIF (EXIF Viewer’s action extension). The field is listed under “Image”. Or drop the photo into the free online EXIF viewer.

Related tags

Image Height (Exif Image Height / Pixel Y Dimension) — Height of the image in pixels, as recorded in the EXIF.
Orientation — How the stored pixels should be rotated or flipped for display. The pixels themselves aren't rotated.
X Resolution / Y Resolution (DPI) — The intended print density in pixels per Resolution Unit — what everyone calls the DPI. It's a label and does not affect the pixels.