The UIDAI allows Aadhaar photo updates, but the process is slightly different from other updates.

Credits- UIDAI
Aadhaar Update: An Aadhaar card is an important identification document for residents of India, which is now linked with every other important document. Due to people's personal/professional reasons to update their Aadhaar photo because it is old, unclear, or does not match their current appearance. The Unique Identification Authority of India (UIDAI) allows Aadhaar photo updates, but the process may vary from online to offline, as it is slightly different from other updates.
Aadhaar photo can't be updated/changed completely online, as UIDAI doesn't give permission to photo uploads through the website. But you can book an online appointment after doing online booking to save time, and then visit an Aadhaar Seva Kendra for the photo update.
This online step helps reduce waiting time at the centre.
If you want to update your photo offline, you must visit an Aadhaar Enrolment or Aadhaar Seva Kendra. Follow these steps:
After submission, you will receive an Acknowledgement Slip with a URN to track status.
The updated Aadhaar photo is usually reflected within 7 to 30 days.
While Aadhaar photo updates cannot be done fully online as per UIDAI rules. UIDAI has made the process simple through appointment booking and quick offline services. Updating your photo helps keep your Aadhaar details accurate and up to date.