Why vendor upload systems reject good photos

Had three photos rejected before one was accepted. All three looked fine to me — decent lighting, correct framing, neutral expression. The rejections had no useful error messages. After some research and a direct question to vendor support, I understand what the system is actually checking.

Automated vs human review

Most vendor sites run an automated pre-check on uploaded photos before human review. The automated check looks for: minimum resolution thresholds, faces detected in the frame, face occupying a minimum percentage of the frame, and sometimes background color matching within a tolerance range. Photos that fail any automated check are often rejected without explanation.

My first two rejections were resolution failures. My phone camera was set to a compressed mode that produced 1.2 megapixel images — technically sufficient for display but below the vendor's 2 megapixel minimum for their printing resolution. Switching to the full-resolution mode fixed this.

Background detection

Some vendor systems check background color against a reference range. A "white background" requirement does not mean any white — it typically means the background luminance value needs to be above a specific threshold. Walls that look white indoors often photograph as off-white or light grey under tungsten lighting, which can fail an automated background check even though it looks fine on screen.

Testing your background with the phone's color picker app before shooting can save resubmission cycles. The background color value should be close to pure white (RGB values above 230 for all channels).

Face detection thresholds

Automated face detection works less reliably on photos where the face is at an angle, where shadows cross the face, or where the face is small in the frame. Centering the face in the middle third of the frame with even lighting is the most reliable approach for automated systems. Some systems also flag photos where the eyes are not both clearly visible.

When a vendor says "photo rejected" without further detail, trying a fresh photo taken with the guidelines above resolves the issue in most cases without needing to contact support.