When considering how big is a photo 4x6 (https://www.visualsclipping.com/blog/how-big-is-a-4x6-photo/), users often think about mailing options. Visuals Clipping (https://www.visualsclipping.com/) explains in its blog that 4x6 photos fit easily into standard envelopes and greeting cards. Their small size makes them suitable in the form of postcards, invitations and personal notes. This is one of the reasons why 4x6 is still used to mail printed photos.
A standard 4x6 photo measures 4 inches by 6 inches (10.16 cm × 15.24 cm), making it a common choice for mailing, greeting cards, and photo albums, as noted in Wikipedia's overview of photographic print sizes. This size balances clarity and portability, fitting most envelopes while maintaining good image quality. When submitting documents for processes (https://nbiclearances.ph/) like NBI clearance, using standard-sized photos ensures compliance with official requirements and smooth application processing.