Guides & how-tos

PNG to SVG isn't a normal conversion — it's tracing, and it only works on some images. Here's how to do it and what actually comes out.

Embedding an image directly in your code is occasionally exactly right and usually a trap. Here's the difference.

Plenty of forms accept a PDF and nothing else. Turning your photo or scan into one takes seconds.

Both sides of an ID, a multi-page contract, a stack of receipts — here's how to get them into one properly ordered PDF.

iPhones save photos in a format Windows, older software, and plenty of upload forms still choke on — here's the quickest way out.

You saved an image from the web and got a file your software refuses to open. Here's the fix, and the reason it happened.

SVG is the better format right up until something refuses to accept it. Here's how to convert without regret.

The cheapest page-speed win available, and it takes seconds. Here's when it's worth doing and when it isn't.

A format from the early Windows era that occasionally still turns up — usually attached to a very large file.

PNGs are often several times larger than they need to be. Converting to JPG is usually the fix — with one important exception.

Converting JPG to PNG is easy. Knowing what it actually gets you — and what it definitely doesn't — is the useful part.

Facebook has four different image slots and four different sizes. Here's the pixels for each, and why a plain resize squashes a cover photo.

1080x1080 is square and your photo probably isn't. Lock the aspect ratio and you get 1080x810; unlock it and the picture stretches. Here's the route that works.

Instagram will crop your photo whether you choose the crop or not. Better to choose it yourself.

Your thumbnail is the advert for your video, and it'll be seen tiny. Design for that and it works.

Square is the default shape of profile pictures and product grids. Cropping to it properly takes ten seconds.

Round avatars and logos need a transparent background to actually look round. Here's how to get one that survives.

Sideways phone photos and backwards selfies both have simple fixes, and one genuinely interesting cause.

Sometimes 'half the size' is a far more useful instruction than working out what half of 4032 pixels is.

The most powerful edit available, and the one people do most carelessly. A few rules make the difference.

The most useful image operation there is — and the one with the most misconceptions attached to it.

20KB is smaller than any one-click preset, so the tool has to shrink your photo's dimensions to get there. Here's how to hit it and keep it sharp.

1MB is a generous target: you usually keep full resolution and barely lose sharpness. Here's how to hit it, and when it gets harder.

A few seconds of animation can outweigh a whole page of photos. Here's how to get it under control.

Application forms and portals love strict limits like 50KB or 100KB. Here's the fastest way to actually hit them.

PNGs get heavy fast. Here's how to shrink one without wrecking the transparency or the crisp edges you kept it for.

JPG compression is invisible until suddenly it isn't. Here's where the line sits and how to stay on the right side of it.

Turn a signature on paper into a clean transparent PNG you can drop onto any document. The trick is a good scan and saving it the right way.

Background removal went from a specialist Photoshop skill to a one-click job. Here's how to get a clean result.

A watermark is a deterrent, not a lock. Here's how to add one that does its job without ruining the photo.

Text on a photo is easy to add and easy to make unreadable. The difference is almost always contrast.

A border is a small thing that solves a few real problems, including one you've probably run into without naming it.

One image out of many, with nothing cropped off. Useful for comparisons, before-and-afters, and anything with an upload limit of one.

You can absolutely take your own passport photo. Most rejections come from a handful of avoidable mistakes.

Same face, same country, different rules — and the difference is what gets applications bounced.

White is the common answer, not the only one — off-white, cream and light grey are each named by a specific authority. The exact background wording for four countries, traced to source.

The difference between mixing light and mixing ink — and why a screen can show colours a printing press physically can't reproduce.

The UK prints at 45 x 35 mm, but the online upload wants pixels, not millimetres, and both must be under a month old. The full spec from GOV.UK, and where it trips people.

The single coloured square every digital image is built from — what one pixel actually stores, and why you can see them when you zoom in.

Both handle photographs well, so the real question is smaller-file-for-the-web versus opens-everywhere. Here's how to call it, and when converting won't help.

China is one of the few countries that does not use 35 x 45 mm. The real 33 x 48 mm spec, the both-ears rule, and why the file-size numbers everyone quotes are not official.

The 35 x 45 mm size every site quotes is a convergence, not an EU rule - the European Commission asks only for an ICAO-compliant photo. What that means in practice, and whether you can reuse a passport photo.

One counts the pixels in a digital image; the other counts the ink dots a printer lays down. They get used interchangeably, and here is when that is fine and when it will bite you.

AVIF squeezes files smaller; WebP is easier to make and opens in more software. For most sites one of them is the clear pick — here's which, and why.

Canada's 50 x 70 mm size is unlike the US square or the 35 x 45 mm most countries use, and IRCC requires a commercial studio to take and print the photo, unedited. The full spec, and where it trips people.

What the US and UK accept for an infant's passport photo: which pose rules relax for a baby, which don't, and how to take one at home without a studio.

The format that squeezes a photo smaller than JPEG or WebP by borrowing the AV1 video codec's compression. What it is, which browsers open it, and its one real catch.

A local shop photographs you and prints a compliant photo for a fee; your own phone does the same for free if it meets the spec. When each option is the right call.

The Indian passport photo upload is 630 x 810 pixels and under 250 KB, on a 7:9 rectangle. The 2 x 2 inch square everyone publishes is the visa spec, and mixing them up costs an application.

The full US passport photo spec, straight from the State Department: 2x2 inch square, head height, background, glasses and recency rules, plus the separate online-upload limits.

Every passport photo has to satisfy the same handful of rules; only the exact numbers change by country. Here is the full requirement list, with US, UK and Canada figures traced to source.

There's no single worldwide passport photo size. Most countries use 35x45mm, but several major ones don't — here's each size, traced to the government that sets it.

The same photo, half the size on your iPhone or readable everywhere else. Which one you want depends entirely on where the picture is going next.

The word doesn't mean a chip or a fingerprint. It means a photo a computer can match your face against — which is why the rules are so specific.

Two formats, one decision that turns almost entirely on whether your image is a photograph or a graphic. Here's how to call it every time.

The format behind half the 'why won't this open' moments online — smaller than JPG and PNG, supported by every browser, and rejected by plenty of desktop software.

The specific things that get a passport photo rejected, drawn from what the US, UK and Canada actually publish — and the rule they quietly disagree on.

Both formats keep transparency, so the choice for a logo comes down to a single trade: WebP is smaller, PNG opens everywhere. Here's which to reach for.

The reason a photo you keep editing and re-saving slowly turns to mush — a photocopy-of-a-photocopy effect built into how JPG works.

The number behind 'true colour', the 256-colour ceiling on GIFs, and why a smooth sky sometimes turns into visible stripes.

A plain-language map of the formats you actually run into — what each is good at, what it's terrible at, and which one to reach for.

The real amount of detail in an image, counted in pixels — and why it's a different thing from megapixels, DPI, and how big the picture looks on screen.

The reason a punchy photo sometimes turns dull the moment you post it online — a mismatch between the colours your file uses and the ones the web expects.

One stores a grid of pixels, the other stores drawing instructions — which is why the size you pick when exporting a PNG is permanent.

The shape of your image, independent of how big it is — and the reason something always gets cut when the shape doesn't match.

One kind of compression gives every pixel back exactly. The other throws some away for good. Knowing which you're using decides what you can undo.

A fourth value on every pixel that says how see-through it is — and the reason a logo sometimes arrives with a white rectangle around it.

Some e-visa applications have no photo field at all. Every photo site still publishes a size for them, because a photo site is what they are.

Your photos carry a hidden record of how, when, and sometimes exactly where they were taken.

A number people obsess over for screens, where it does nothing at all — and under-think for print, where it decides everything.

Usually it's one of four things, and the first one accounts for most of it. Here's how to diagnose it in ten seconds.