A clear answer. Here’s how.
Scales a preview tile proportionally to the selected maximum dimension, without enlarging smaller sources, and repeats it 3 × 3. Exports the repeated preview as PNG, capped at 4 million pixels. This reveals edge discontinuities but does not repair seams, blend borders or claim that a texture is seamless. Supports PNG/JPEG/WebP up to 10 MB and 4 million decoded pixels per file. Browser decoding and single-frame PNG re-encoding remove source metadata/colour profiles; no files leave this device.