Guides & how-tos

One Camera setting makes new iPhone photos JPG. A second decides what your computer receives. Neither touches the photos you already took.

Both phones can already make a PDF from a photo, if you know where the option hides. Here are the built-in routes, and when a browser tool is the better pick.

The right conversion for a small, flat preview or thumbnail - and why a logo with transparency should go to PNG instead.

Pull a clean, lossless still out of a GIF, including the first frame of an animation. What the conversion keeps and what it cannot recover.

The right conversion when you need to keep transparency or a lossless copy - and when converting to JPG is the better call instead.

A BMP lands in your inbox or a scan folder and it is far too big. Converting it to JPG takes a second - here is the whole process, and the one case where JPG is the wrong target.

PNG is the right landing format for a HEIC photo you plan to edit, not one you just want to share. Here is what the lossless conversion does, and doesn't, do.

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.

Preview resizes the file in place and Photos resizes a copy on export. Here is which to use, how to batch it, and when a browser tool is simpler.

Preview and Photos both crop in a few clicks, but they treat your original differently. Here is which one to use, and when a browser tool is quicker.

The Photos app turns a picture in a few taps. The harder case is a photo that looks fine on the phone and arrives sideways somewhere else.

LinkedIn's profile banner is an extreme 4:1 strip and the profile photo shows in a circle. Here are the pixels for each slot, and why a plain resize stretches a banner.

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.

A one-click tool gets you under 50KB. But 50KB means two different numbers depending on who counts, and a form that counts the smaller one can still reject the file.

200KB is the most generous of the common upload caps, so it is the one where a scanned certificate or ID keeps its fine text. Here is what to expect.

100KB is a common upload cap on job and exam portals. A dedicated one-click tool aims for it with no settings to touch — here is what to expect from your photo at that size.

Most email services cap attachments at 25MB, and encoding overhead trims that further. Here's how to shrink a photo to send it as a real attachment, and how small to actually aim.

2MB is a common upload cap and a loose target. Most photos hit it with quality alone, and files already under it are handed back untouched. Here's how, and when it gets harder.

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.

Isolate a product and composite it onto pure white for a marketplace listing, without uploading a shot you haven't launched yet. The White option is the step people miss.

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.

A passport photo file has no built-in print size. Here is how to get exactly 35 x 45 mm or 2 x 2 inches out of a home printer, and when not to try.

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.

Clothing rules for passport photos, straight from the US State Department, HM Passport Office and IRCC - including the uniform ban and the white-shirt trap.

The honest answer most sites won't give: for an adult Bangladesh e-passport, you probably don't submit a photo at all.

Brazil is the honest case: credible sources cite three different sizes. Check yours, then pick the match - and know the photo is often taken on-site.

The trap: a Canada visa photo is 35x45mm, not the 50x70mm passport size. One spec covers TRV, study, and work permits.

Almost every site gives you the UK passport spec by mistake. The gov.uk visa photo is digital-only, with no millimetre size at all.

The unusual 33x48mm size Western photo labs cannot produce, plus the 80KB file cap and the both-ears rule that catch people out.

The Türkiye e-Visa asks for no photo at all. Only the in-person consular sticker visa needs one - 50x60mm on white.

The official e-visa spec: 4x6cm, under 2MB, no glasses. Not 35x45mm, and not the 1024KB limit third-party sites keep repeating.

A geometric trap: Immigration NZ's online photo (3:4) and paper photo (35x45mm) are not the same shape. Use the one for how you are applying.

Almost every guide gives you the wrong photo. The Visit Saudi portal wants a small 200x200px square, not a 2x2in print.

The size is the easy part. The thing that stops Pakistani passport and e-visa uploads is a ~60KB file-size cap.

The size most of the world uses, with two catches: your consulate has the final word, and a K-ETA is not a visa.

Mexico asks for two 35 x 45 mm photos, no glasses, no earrings, and taken within the last 30 days - a freshness rule most countries skip. The full spec from the SRE, and why a US 2 x 2 inch photo will not do.

Japan is the country with no national visa photo size: its foreign ministry delegates it to the mission handling your case. The sizes in play, and why 45x45mm is not the standard.

For a Philippine passport the DFA captures your photo at the appointment — you do not bring one. Here is the 35 x 45 mm standard, when it still matters, and the appearance rules that actually decide whether your capture passes.

The DS-160 upload wants an exact square, 600 to 1200 pixels, under 240KB - numbers a printed passport photo misses. Here is the real State Department spec.

The Nigeria Immigration Service asks for two white-background prints endorsed by a guarantor, then captures your biometric photo in person - and publishes no mm, DPI, or file-size number. What that means for the photo you bring.

Australia publishes a size range, not a single 35 x 45 mm number, and the 35x45 everyone quotes is only its low corner. The full spec from the Australian Passport Office, and the rules that get photos knocked back.

The uncompressed Windows format from the early PC era - why a BMP is enormous, where it still turns up, and what to use instead.

The format that refuses to die: 256 colours, looping animation, and a place in internet culture long after better formats arrived.

The format almost every photo online is saved in - what it does well, what it quietly costs you, and when to reach for something else.

The format behind almost every logo, screenshot, and icon with a see-through background: lossless, transparent, and much heavier than JPG for photos. What a PNG file actually is.

The format every iPhone photo is saved in by default: a modern container that roughly halves file size, yet one that a lot of software still cannot open. What a .heic file actually is.

One kind of compression is reversible and one isn't. Knowing which you're using decides whether you can edit a file again later without watching it fall apart.

The image format print shops and archives rely on: lossless, high bit-depth, and far too heavy for the web. What's inside a TIFF, why it's so big, and what to do when a site won't take one.

The image format that stores a picture as shapes written in text, so it stays sharp at any size. What's inside an SVG, what it's for, and where it gets refused.

Smiling is out almost everywhere, but the glasses rule genuinely differs country to country. What the US, UK, Canada and Australia each require, from source.

They aren't really rivals for the same job. One is drawing instructions, the other a grid of pixels - which settles the choice before file size ever comes up.

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.