Your passport photo can be right and the DS-160 upload still wrong.

Same sitting. Two outputs.

A good capture can feed both a passport print and a DS-160 upload. The print is a 2×2 inch paper product. The portal is a digital product: square JPEG, 600×600 to 1200×1200, 240 kB or less, sRGB, head 50–69% chin to crown, eyes 56–69% from the bottom.

Local passport sizes are not 2×2. A UK 35×45 mm print, a Nigerian passport booth file, or a 10 MB studio scan can be a legal passport photo and still bounce in CEAC. “Can I use my Nigerian / UK passport photo?” means: you may reuse the sitting if you re-export to the digital rules. You may not upload the print scan or the huge studio TIFF and hope.

What usually breaks the reuse

A multi-megabyte passport scan. An HEIC export from a passport app. A rectangular crop that is not square. A file the official crop tool forced to 600×600 without fixing head height or background.

If CEAC already rejected the file, the passport was not the problem. The digital job was.

Questions

The photo is already in my current passport. Can I scan that page?

No. That is a photo of a photo, with laminate glare. Reuse the sitting only if you still have the digital original or you take a new capture.

Is a US passport photo the same as a DS-160 photo?

Face and background rules are close. The upload still has to be a square sRGB JPEG in the pixel and kilobyte window. The passport book does not prove that.

How recent does it have to be?

Taken within six months, and a current likeness. A passport issued last year does not make a three-year-old studio file current.