In-depth guides on file tools, formats and privacy
Long-form, technical articles written by the team that builds DuneTools. Format comparisons, step-by-step workflows, privacy explainers and developer references, all free, all linked to the relevant tools.
21 guides · 211 min total reading
PDF Guides
PDF to JPG vs PDF to PNG: Which to Choose (2026 Decision Guide)
Quick decision guide on whether to convert PDF to JPG or PNG. Resolution, quality, file size, transparency, every trade-off explained with real benchmarks.
PDFHow to Compress a PDF for Email: The Complete 2026 Guide
Email providers cap attachments at 25 MB (Gmail), 20 MB (Outlook), 10 MB (many corporate). Here's how to compress any PDF to fit, what to compress vs preserve, and the privacy trap most online compressors hide.
PDFDuneTools vs ILovePDF: Honest 2026 Comparison
Detailed comparison of DuneTools and ILovePDF for PDF tools, privacy, file limits, features, and pricing. Which one to use for which job, with no marketing fluff.
PDFDuneTools vs SmallPDF: Honest 2026 Comparison
Detailed comparison of DuneTools and SmallPDF for PDF tools, privacy model, file limits, features, pricing. Two solid options compared with no marketing fluff.
Image Guides
How to Reduce Photo Size for Email (Gmail, Outlook, Yahoo Limits 2026)
Practical guide to reducing photo size below the 25 MB Gmail / 20 MB Outlook / 25 MB Yahoo email attachment limits. Resolution, format, batch tips.
IMAGEWebP vs AVIF in 2026: Which to Use for Your Website
Honest 2026 comparison: WebP vs AVIF for web performance, browser support, file size, encoding speed and the practical fallback chain, with real benchmarks.
IMAGEHow to Compress an Image for WhatsApp Without Losing Quality
WhatsApp ruins your photos with aggressive compression. Here's how to send a photo at full quality, the exact size limit that triggers heavy compression, and the small workflow that fixes it once and for all.
IMAGEDuneTools vs Squoosh: Honest 2026 Comparison
Detailed comparison of DuneTools and Google's Squoosh for image compression, both are local-first, but the targets are different. Pick the right tool for the job.
IMAGEDuneTools vs TinyPNG: Honest 2026 Comparison
Detailed comparison of DuneTools and TinyPNG for image compression, privacy, file limits, formats supported, output quality, and pricing. Honest pros and cons of each.
IMAGEHow to Make a Transparent PNG: The Complete Guide
Transparent backgrounds are the building block of every modern logo, sticker, and overlay. Here's how PNG transparency actually works, the four ways to remove a background, and why most online tools secretly destroy your alpha channel.
IMAGEHow to Resize an Image for Instagram (Every Dimension Explained)
Instagram's eight different image dimensions, feed, portrait, story, reel, carousel, profile, ad, IGTV, explained with the exact pixel sizes, when to use each, and what Instagram silently does to anything that doesn't match.
IMAGEHow to Compress Images Without Losing Quality (2026 Guide)
Technical guide to compressing JPG, PNG and WebP up to 80% with no visible loss. Algorithms, formats, common mistakes, and private tools that don't upload your photos to the cloud.
IMAGECrop Images Online: The Complete 2026 Guide
How to crop images to the exact pixel for Instagram, YouTube, Twitter and web. Presets, rule of thirds, batch cropping, all without uploading your photos to the cloud.
IMAGEFavicon Generator: The Complete .ICO Guide (2026)
Everything you need to know to create a professional favicon: ICO vs PNG vs SVG, multi-size containers, Apple Touch Icons, Android manifest, dark mode, and HTML installation.
IMAGEHTML to Image: A Developer's Guide (2026)
How to convert HTML, CSS and DOM nodes to PNG/JPG images. Use cases, libraries, browser APIs, OG image generation, watermarks, and how to do it without uploading code to a server.
IMAGEImage Formats Compared: JPG vs PNG vs WebP vs AVIF (2026)
Pick the right image format for every use case. Lossy vs lossless, compression efficiency, transparency support, browser compatibility, and when to use each in 2026.
General Guides
Video Guides
Privacy Guides
Audio Guides
How to Extract Audio from YouTube, TikTok and Any URL (2026 Guide)
Complete guide to extracting audio from any video or URL, YouTube, TikTok, Instagram, direct MP4. Method comparison, format, quality and privacy. No installation.
AUDIOHow to Merge MP3 Files: The Complete 2026 Guide
Complete guide to merging MP3, WAV and M4A files. Gapless vs crossfade, bitrate matching, lossless joining, privacy. With or without re-encoding, every method explained.
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