File Format Guides
In-depth, source-checked articles for anyone who works with images, PDFs, or video files. Each guide is reviewed against W3C/WHATWG specifications, IETF RFCs, ISO/IEC media standards, and the official documentation of libraries we use in production before publication.
JPG vs PNG vs WebP vs AVIF: Which Image Format Should You Use in 2026?
AVIF now has 95%+ browser support and WebP has been universal for years. Here's when to use each format — with real file-size numbers and the compatibility gotchas that still matter.
·10 min read·OnlyFormat Editorial TeamHEIC to JPG: The Complete Guide to Converting iPhone Photos (2026)
iPhones have shot in HEIC by default since iOS 11 (2017), but HEIC still fails to open on many Windows PCs, email clients, and legacy web apps. Here's what HEIC actually is, when you need to convert, and how to do it without quality loss.
·8 min read·OnlyFormat Editorial TeamHow to Reduce PDF File Size Without Losing Quality
A 40 MB PDF is usually 90% embedded images at full resolution. Here's how PDF compression actually works — image downsampling, stream compression, font subsetting — and the fastest way to shrink a file without visible degradation.
·9 min read·OnlyFormat Editorial TeamLossy vs Lossless Compression: What Every Image Workflow Needs to Know
Lossy compression discards information you (usually) can't see. Lossless preserves every byte. The difference determines whether you can re-edit a file, whether it survives repeated saves, and whether it's safe for archival. Here's the full picture.
·8 min read·OnlyFormat Editorial TeamAVIF vs WebP: The Modern Image Format Comparison (2026 Edition)
AVIF consistently beats WebP on file size at equivalent quality — typically 20-30% smaller — but encoding is slower and older browsers (Safari on iOS 15) still don't support it. Here's when each format actually wins.
·9 min read·OnlyFormat Editorial TeamBMP to PNG: Modernizing Legacy Bitmap Files
BMP files are typically 10x larger than the equivalent PNG, yet they still turn up in industrial imaging, legacy Windows apps, and old archives. Here's what BMP actually is, why it's still around, and how to modernize without losing any pixel data.
·7 min read·OnlyFormat Editorial TeamSVG to PNG: Vector to Raster Without Quality Loss
SVG is resolution-independent; PNG is not. Converting between them looks simple but has real gotchas — DPI choice, transparency, foreignObject, embedded raster content. This is how to rasterize SVG correctly for icons, email, and social.
·8 min read·OnlyFormat Editorial TeamGIF to MP4: Why Modern Video Wins Every Time
A 30-second GIF is often 20MB; the same clip as MP4 is 1.2MB with better quality. Here's why GIF is a terrible video format, why Twitter/Discord silently convert your GIF uploads anyway, and how to do the conversion yourself.
·8 min read·OnlyFormat Editorial TeamPDF Merge vs ZIP: Which Is Right for Sharing Documents?
Merging into a single PDF gives you cross-document search and guaranteed deliverability; ZIP preserves originals and mixed file types. The right choice depends on what the recipient will actually do with the files.
·7 min read·OnlyFormat Editorial TeamBatch Image Compression for Shopify and Etsy Sellers: A Complete Workflow
Product-photo file size directly affects your conversion rate via LCP and Core Web Vitals. Here's the full workflow — specifications, formats, target resolution, quality settings — for optimizing images for Shopify and Etsy in 2026.
·9 min read·OnlyFormat Editorial TeamCSV vs JSON vs XML: Choosing a Data Format in 2026
CSV for flat tables, JSON for APIs and configs, XML where enterprise tooling already owns it. Here's the decision tree with real file-size numbers, parsing trade-offs, and when converting between them makes sense.
·10 min read·OnlyFormat Editorial TeamBase64 Encoding Explained: When and Why to Use It
Base64 is not encryption — it's a binary-to-text encoding that inflates files by ~33%. This guide covers where it's genuinely needed (email MIME, data URLs, JWT) and where it's misused (as security, as the default for big inline images).
·8 min read·OnlyFormat Editorial TeamYAML vs JSON for Configuration Files: Which Should You Use?
Kubernetes, GitHub Actions, and Ansible picked YAML. VS Code and npm picked JSON. Here's why — plus the Norway problem, indentation landmines, and when to migrate in either direction.
·8 min read·OnlyFormat Editorial TeamMarkdown to PDF: A Developer's Documentation Workflow
Three main conversion paths — browser print, Pandoc/LaTeX, and headless browser — each with different trade-offs on styling, code highlighting, math rendering, and batch processing. Here's how to pick for your document type.
·8 min read·OnlyFormat Editorial TeamJPEG Quality 70 vs 85 vs 95: Which Setting Should You Actually Use?
The JPEG quality slider isn't a linear dial. Quality 85 is where every serious tool (Photoshop, Adobe, WordPress, Shopify) lands by default — and for good reason. Here's what each setting actually produces, with file-size curves.
·7 min read·OnlyFormat Editorial Team