- Does this add detail that was not in the original?
- No, and be wary of any tool that claims otherwise without telling you it is generating pixels. A detail not captured by the camera is not recoverable — what this does is enlarge cleanly and restore the local contrast that interpolation loses, so the result looks like a good enlargement rather than a blurry one.
- Why is this better than just typing a bigger number into the resizer?
- One big jump asks the browser's scaler to invent most of the pixels in a single pass, which is exactly what it is worst at. Doubling repeatedly keeps every pass inside the range the scaler handles well. The resizer here now uses the same stepped path whenever you enlarge, so you get this either way — this page just makes the common 2× and 4× cases one click.
- How much sharpening should I use?
- Around 60% suits most photographs. Text and line art take more; skin and sky take less. If you can see a pale outline tracing high-contrast edges, you have gone too far — that halo is the giveaway of an over-sharpened image and it will not print well.
- Why is 4× disabled for my photo?
- Browsers cap how large a canvas can be, and the ceiling is roughly 16 megapixels on the strictest of them. A 12MP phone photo at 4× would be 190MP, far past it, so the larger factors are switched off rather than handing you a blank file.
- Can I upscale a photo for printing?
- You can, and a stepped enlargement prints better than a stretched one, but it is no substitute for the resolution the shot needed. As a rule of thumb print wants around 300 pixels per inch, so a 1000px-wide image is genuinely good for about 3 inches — enlarging it to fill A4 will show.
- Is my photo uploaded anywhere?
- Every step happens inside your browser tab using Canvas and WebAssembly. The file is never uploaded, so there is no server copy to delete and no account to create.