LivreImage
PT

Guides

Straight explanations about digital images — what each format does, how to reach the size a form asks for, what your photo reveals without you knowing. Every guide lists the official sources it used.

All guides

Image formats JPG, PNG, WebP, AVIF or HEIC: which image format to use, and when JPG, PNG, WebP, AVIF, HEIC, GIF, SVG, BMP and ICO compared: compression, transparency, browser support and which one to pick for each job, with sources. 7 min read Image formats Transparent backgrounds: what the file stores, and why it sometimes turns black What an alpha channel stores, which formats keep transparency, why cutouts turn black or white as JPG, and how to fix the halo around the edges. 8 min read Image formats HEIC explained: what your iPhone saves, where the file opens, and what converting leaves behind HEIC explained: what an iPhone photo file holds, where it opens on Windows, Android and browsers, how to shoot JPEG, and what converting leaves out. 8 min read File size and compression How to reduce a photo's file size without visible quality loss Pixels, quality and format: what each does to a photo's file size, when to resize, when to compress, and how to hit an exact KB limit on a form. 7 min read Images for websites WebP and AVIF on your website: measured savings, browser support and fallbacks What published tests say WebP and AVIF save, which browser versions open them, how to set up a picture fallback, and when converting isn't worth it. 7 min read Printing and resolution How many pixels you need to print a photo at 4×6, 8×10, Letter or A4 The pixels = inches × PPI formula, charts for 4×6, 5×7, 8×10, 11×14, Letter and A4 at 300 and 150 PPI, and why the 72 DPI in your file changes nothing. 8 min read Document and ID photos Passport and ID photo sizes by country, with pixels and upload limits Official passport and visa photo sizes for the US, UK, Schengen, Canada, Australia and India in mm, inches and pixels, plus each upload's file limits. 8 min read Sending and sharing How to send photos without losing quality, channel by channel What iMessage, RCS, WhatsApp, Telegram, email and cloud links do to a photo, each one's official limit, and how to send the original file. 7 min read Privacy Does that image tool upload your photo? Check it yourself Use your browser's Network panel and the airplane-mode test to see whether an online image tool uploads your file or processes it on your device. 8 min read Privacy Photo metadata (EXIF): what your pictures reveal and how to strip the location What EXIF stores (GPS, date, device), how to view it on Windows, Mac, Android and iPhone, which platforms keep it, and how to share without location. 8 min read

How we write the guides

Every guide starts from a real question asked by people who use the tools. Numbers, limits and official requirements are checked against the primary source — the agency, the manufacturer or the technical specification — and the list of sources sits at the end of the page, with the date we read them.

We use artificial-intelligence tools to support research and drafting. What gets published is checked against the cited sources; what we could not confirm is left out.

Rules change. When a guide is revised, the update date at the top changes with it. If you find something wrong, tell us through the contact page: corrections go in first.

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