Free here means the Canvas path, not a fake trial watermark
You can grow a photo in this tab without creating a Convertify4u account. After the page loads, encoding is local — we do not need your file on a server to interpolate pixels. That is the privacy story and the reason there is no signup wall on everyday jobs. Pro on this site is for OCR, multi-file VPS queues, and oversized cloud workers on other tools; this enlarger is Instant Canvas, not a metered GPU farm. Native JPG/PNG/WebP; convert HEIC first; GIF first-frame to a still raster (palette tricks are a GIF Maker topic). Cap 10,000 px per side. Optional sharpen, contrast, and brightness. Drag-and-drop on desktop; on phones use the file picker. If a competitor watermarked your download until you paid, that is not this workflow. Compress after scale if you need a smaller share. Locked-down work PCs that block installs can still run a browser. We do not store the upload because there is no upload on this path. If the result looks plastic at 100% zoom, the original was already empty of detail — recapture rather than stacking another 2×. School Chromebooks and guest Wi-Fi work the same: the interpolation never leaves the machine.