Tutorials — Practical Guides for Online Tools

Why visa photos get rejected: 7 fixable reasons Seven checkable reasons behind most rejected visa photos — background, head ratio, glasses, file size and more. Fix them before you submit. 2026-10-02 · ID & Documents

Head ratio in ID photos: 50-69% vs 70-80% The two head-ratio ranges used by passport authorities, why the US and Schengen differ, and how to measure your own photo in under a minute. 2026-10-02 · ID & Documents

How to compress a photo to an exact KB size Some portals demand under 240 KB, others between 40 and 120 KB. How to hit a target file size without wrecking the image. 2026-10-02 · Image Tools

Change a photo background to light grey or white Schengen and UK applications want light grey; the US and Korea want pure white. Replace the background in your browser without uploading the photo. 2026-10-02 · ID & Documents

Print passport photos at home on a 6-inch sheet A 6-inch print sheet holds several ID photos at 300 dpi. How to lay them out, what paper to use, and how to cut them accurately. 2026-10-02 · ID & Documents

Passport and visa photo sizes by country Photo size rules differ by country: 2x2 in for the US, 35x45 mm for the UK and Schengen, 33x48 mm for China. Full table inside. 2026-10-02 · Image Tools

How to compress an image to 100 KB Forms, portals and email all cap file size, and "under 100 KB" is the most common. Here is the setting to change first. 2026-10-01 · Image Tools

How small should a video be? Sizes that work Messaging apps, email and the web tolerate very different video sizes. Here are the bitrate and resolution targets to use. 2026-10-01 · Video Tools

How to convert HEIC to JPG on any device Newer iPhones save photos as HEIC, which Windows and many upload forms cannot open. Here is how to convert a batch to JPG. 2026-10-01 · Image Tools

How to change a photo background to white White backgrounds are required for passport photos, ID cards and most e-commerce listings. Here is how to get a clean result. 2026-09-30 · Image Tools

ID photo sizes and background colours Which ID photo size and background colour to use for passports, visas and forms, with a millimetre-to-pixel reference. 2026-09-30 · Image Tools

How to get a video under 10 MB Gmail, WhatsApp and Outlook all cap attachments at different sizes. Here is how to hit a 10 MB target and keep it watchable. 2026-09-29 · Video Tools

JPG vs PNG vs WebP vs AVIF: which to use Six image formats, six jobs. How JPG, PNG, WebP, AVIF, GIF and SVG compare on transparency, compression and support. 2026-09-28 · Image Tools

QR code size and scan distance explained A QR code that scans on your monitor can fail on a poster. The size-versus-distance rule, quiet zone and contrast rules. 2026-09-27 · Image Tools

Shrink a video without wrecking the quality Almost all of a video file size comes down to three settings: resolution, bitrate and frame rate. Here is how to choose each. 2026-09-26 · Video Tools

Six reasons your JSON fails to parse Trailing commas, single quotes, unquoted keys, comments and invisible characters cause almost every JSON parse failure. 2026-09-25 · Developer Tools