Preparing an image before you publish it

Rotation is two different operations

A photograph taken with a phone held sideways is very often stored the same way up as every other photograph, with a small EXIF flag recording which way round it should be displayed. Your phone honours the flag. Your desktop viewer honours the flag. A good many upload pipelines strip metadata before doing anything else, and then see the pixels exactly as they are, which is sideways.

This is why an image that looks correct everywhere you have checked arrives rotated on somebody else’s site, and why “but it looks fine on my computer” is true and unhelpful.

Rotating the image turns the pixels, so the result does not depend on anything downstream reading a flag. It is the version that survives.

Flipping is a different operation that people reach for in the same moment. It mirrors, and mirroring is not rotation: a flipped photograph has back-to-front text, a reversed parting, and a wedding ring on the wrong hand. Selfie cameras preview mirrored and save unmirrored, which is why your own face looks subtly wrong in your own photographs, and flipping is how you get the preview back.

Upscaling adds pixels, not detail

Upscaling makes an image larger by interpolating: each new pixel is a guess from its neighbours. The result is bigger and slightly softer, and it contains no information the original did not.

That is worth saying plainly because the expectation runs the other way. Detail that was never captured cannot be recovered. A licence plate too small to read at the original size is too small to read at four times the size; it is just blurrier over a wider area.

What upscaling is genuinely for is meeting a minimum. A marketplace demanding 1,600 pixels on the long edge, a print shop with a size floor, a form that rejects anything under a threshold. Those are real requirements and interpolation satisfies them honestly.

Going the other way is usually the better move. Start from the largest original you have and compress down to what the destination needs, rather than enlarging something already small.

A watermark survives its part of the frame

Watermarking has one decision in it and everything else is detail: where.

A mark in the corner is tidy, unobtrusive, and removed with a single crop. A mark across the middle of the subject cannot be cropped out without destroying the picture, and it is also the mark people find ugly.

There is no arrangement that is both discreet and durable. That is not a limitation of a particular tool, it is a property of putting ink on a rectangle that somebody else can trim. Decide which you want per image: a proof sent to a client can afford to be ugly, and a portfolio piece probably cannot.

Opacity is the other lever, and low opacity fails in the same direction as a corner. Something faint enough to ignore is faint enough to paint out.

Favicons, and the list of sizes nobody needs any more

The favicon generator produces the set, but the set is smaller than most guidance suggests.

A current browser is content with an SVG, which scales to whatever it needs, plus a 32-pixel PNG for anything that will not take one. What extends the list is elsewhere: iOS uses its own 180-pixel PNG for a home-screen icon and ignores the manifest entirely, and Android reads the sizes named in the web app manifest.

The one that is easy to get wrong is the maskable icon. A platform crops it to whatever shape it prefers, and only the middle of the canvas is guaranteed to survive, so an icon drawn edge to edge gets its artwork cut into. A maskable icon needs its own version with the artwork at about 60% on a filled background. Declaring one file as both is the common mistake, and it looks fine everywhere except on a phone.

Do it in this order

Each of these changes what the next one sees, so the order is not arbitrary.

Rotate and flip first, while the image is still at its original size. Both are lossless rearrangements of existing pixels, and doing them before anything that resamples means no quality is spent twice.

Watermark next, because the mark should be positioned against the final framing rather than a crop that has not happened yet.

Resize or upscale after that, so the mark scales with the picture and stays in proportion.

Compress last, always. Every JPEG save is lossy, so a file compressed and then edited and then compressed again carries two generations of loss for one round of work. Keep the original, do the edits, compress once at the end.

Metadata is a separate question worth asking

Rotating, flipping and watermarking all rewrite the picture and none of them remove what the camera recorded about it: the model, the settings, the timestamp, and frequently the GPS coordinates of where you were standing.

If the image is going anywhere public, strip the metadata as a separate deliberate step, and read the guide on what those coordinates give away before deciding it does not matter.

None of this is uploaded

Every tool named here runs in your browser. Photographs are the files people most often have a specific reason not to hand to a stranger, and preparing one for publication should not require publishing it first.