Z.Tools の最新記事。ツールの使い方、プロダクト更新、AI ツール活用、開発ノートを掲載しています。
A short, practical recipe for shrinking phone or camera photos under common email-attachment caps without re-compressing them through three different tools and watching the quality crater.
PNG is not dying. UI assets, icons, screenshots, and technical diagrams all need lossless compression, and OxiPNG is the practical browser-side tool for shrinking them without touching a pixel.
The hero image at the top of your page is almost always the Largest Contentful Paint element. Here is the actual workflow to compress it once, set the right hints, and stop watching it drag your Core Web Vitals down.
AVIF compresses 20-50% smaller than WebP at equivalent quality, but encode time and content type flip the math. Here is the honest decision rule for picking between them in 2026.
Every social platform recompresses your photos on upload. Here is exactly how Instagram, X, and LinkedIn do it, and what to compress beforehand so the platform stops mauling your work.
A practical 2026 decision tree for choosing between WebP, AVIF, JPEG XL, PNG, and JPEG, including the cases where the obviously-best format is the wrong call.
A 4.5:1 contrast pass tells you nothing about whether a colorblind reader can use your UI. Two checks, two answers, and the verdicts often disagree.
The European Accessibility Act has been enforceable since 28 June 2025. Here is what changed for color contrast, who is in scope, and a 30-day plan that does not require a redesign.
A dark-mode toggle does not fix accessibility. Re-test every token pair, fix the bright-link-on-navy trap, and keep focus rings visible. Here's the workflow.
WCAG 2's 4.5:1 ratio and APCA's Lc score don't always agree. Here's where they diverge and how to ship UI that survives the WCAG 3 transition.
Yes, you can keep your brand color and still pass WCAG AA. The trick is knowing which Tailwind shades clear which thresholds, and refusing to use blue-500 for everything.
Three contrast bugs show up in almost every shipped UI: ghostly placeholders, brand blue that misses AA by a hair, and a dark mode without an audit.