Guides
Short, practical guides about file formats and conversion tasks. Each one answers a real question and links to the tool that does the job.
What does 300 DPI mean?Tie DPI to pixels with one formula and a worked print exampleCombining several photos into one PDFCollect many images into a single document ready to printWhat is a CSV file, and why do special characters break in Excel?Why accented characters garble in CSV files, and how to fix itWhat is a file extension?What the label after the dot is, and why it does not define the fileWhat is a favicon, and which sizes do you need?Where the tab icon shows up and which sizes it has to coverReducing a photo's file sizeTwo separate ways to get a file under a KB limitPutting a photo on a white backgroundFilling an empty background versus erasing a real oneRemoving location and EXIF data from photosWhere the hidden location record lives, which channels strip it, and how to verifyHow to create a strong passwordWhy length beats complexity, the random-word method, and a six-question checkWhat is a hex colour code, and how do you read #2F6FED?What the six characters mean, and how to find a colour's codeInstagram and social media image sizesRatios are the lasting part; pixel figures come secondWhat is JSON, and how do you read a .json file?Opening, reading and converting a .json file, in plain languageWhat is Markdown, and how do you read a .md file?What the Markdown marks mean and what to do with a .md fileHow many characters fit where?Common platform limits, the SMS encoding trap, and how to count what you wrotePNG or JPG? Which one, and whenChoosing the right format for photos, screenshots and logosWhat is SVG, and when do you convert it to PNG?How a vector file works and when a PNG export becomes necessaryTurning a phone photo into a PDFConvert a document photo to PDF without a computerHow to create a QR code for freeStatic versus dynamic codes, the right print size, and testing before you printPassport and ID photo sizesWhich country asks for which size, and what it is in pixelsWhat is WebP, and why won't it open?What to do when a saved picture arrives as .webp, and when to convert