What enlarge actually does, and what it does not
Enlarge gives you three settings: 2×, 3×, and 4×. Pick one, and the page pulls the picture up by blending the pixels around each new one, then runs a sharpen pass over the edges. The extra pixels are computed from their neighbours. Nothing is fetched from anywhere else, and a soft face does not turn into one you could recognise.
So a photo that missed focus, or caught a little hand shake, comes out of Enlarge as the same photo with harder edges. There are more pixels. The picture can fill more space. What you can see in it has not grown. If you want it to look less washed out on a big screen, this step helps. If you want the lost information back, this step cannot do that.
Enlarge is interpolation plus sharpening. Not super-resolution, not a neural restore.
Pixels grow by the square
2× doubles the width and the height, so the total pixel count is four times bigger. 4× multiplies both sides by four, so the count is sixteen times bigger. A 3000 × 2000 photo at 4× becomes 12000 × 8000, which is 96 million pixels. That is past the ceiling on the page, and the page will tell you the picture is too large for the browser to handle. Look at the width and height of the original before you pick a factor.
The sharpen slider is yours to set. Push it up and the edges get harder, and so do the white halos, the noise, and the small grain on skin. Pull it down and you get close to plain interpolation, which looks softer. No setting is the correct one. Look at the result before you download it.
- Original around 1500 pixels on the long edge, going to a web page or a chat window: 2× is enough.
- Going on a screen, or into a page of a document: 3× holds up better.
- Original only a few hundred pixels: 4× enlarges the jaggies too, so check the edges first.
It is not the same road as Set size
Set size changes width and height by pixels or by a percentage from 1 to 400, and it can lock the ratio or refuse to enlarge at all. Enlarge works in fixed factors: 2, 3, 4, nothing else. Both recompute pixels. Neither adds detail. If you need one exact width and height, use Set size. If you just want the whole thing a step bigger, use this one.
File size and pixel count are two different things. To make the file smaller, use Shrink file. To change how many pixels there are, use Set size or Enlarge. Enlarging usually makes the file bigger, because the pixels are really there now.
A picture that is too large stops halfway
Past 12000 pixels on a side, or 24 million pixels in total, the page says the picture is too large for the browser to handle. It is not your connection. This browser cannot do the arithmetic. Drop the factor one step, or bring the original down with Set size first and then enlarge. The other order makes no sense: enlarge and then shrink is just the same work done twice.
Output is PNG, and transparency survives
Enlarge always writes PNG. Whatever was transparent stays transparent, with no white fill laid underneath. If you need a JPG, run it through Make JPG afterwards. That is the step where a background colour gets chosen.
Two things do touch the network
When the page opens, the visit is counted by 51.LA. What gets counted is that someone opened the page, not your image files. The pixels and the arithmetic stay in this browser. How files are handled sets out that boundary, and there is no sign-in or account there either.
The other one is cutout. The first time you use Lift the subject, the browser downloads a recognition model from the model publisher into this device's cache. The work still runs on this device. Enlarge does not download that model, and it has no way to send a photo out through cutout.
You download a PNG this device just produced. The original file is still in the folder where it was.
Three looks before you send it
- Check for hard white halos on edges. Text on a dark background shows them first.
- Check whether noise and skin grain got enlarged along with everything else. If so, go back and lower the sharpen.
- Check the size is actually enough. If it is not, run it again at a higher factor.
You can drop up to 40 files at once, and enlarging is one of the steps you can run straight through before downloading the set. The queue only lives in this one visit. Refresh or close the page and anything you have not downloaded is gone. If you want the batch route first, read shrink a batch before email.
To do it now, drop your pictures on the bench, open Enlarge, pick a factor, and look at the edges at full size before you download.