Experiment: A4 vs US Letter output in ColoringPageFromPhoto.com Maker
Date: 2026-11-08 (Beijing)
Browser: Chrome 156.0.8078.80
Input: one locally created synthetic 640x480 PNG; no photograph or user file
Style: Clean Outline
Procedure: Open the local snapshot of the current production homepage, upload the same input for each run, choose A4 then US Letter, generate, save the actual Download PNG output, record result dimensions and file bytes. Compare output PNGs on same 800x800 white canvas, fit each image within 760x760 preserving its aspect ratio, center; threshold each RGB pixel as black if any channel <100; count positions where black/nonblack classifications differ.
Observed: A4 3508x2480 px, 413706 bytes, SHA-256 bd28ae8cab2250ce8950c0408cd69f840d41bbcb1bdc9d35899ceee2bb62afe6. US Letter 3300x2550 px, 416556 bytes, SHA-256 1ed5528250f9ca28a3ac074bb2f6f3cdb21953efd291bccd79f645dbdd59daec. Aligned mask differing positions 4090; A4 black positions 2067; Letter black positions 2649.
Limits: one synthetic input, one browser version, one style, two paper options. No photos, alternative styles, PDFs, physical print, or repeated trials. Mask count is not a quality score, and the test does not establish that either size is better.