Open capability reference
A source-backed map of FormatTailor's image paths, safety limits, and privacy boundary. It documents the product as it exists; it does not pretend every browser or every file behaves the same.
Capability matrix
The table records what FormatTailor accepts and offers. “Runtime-dependent” means the page asks the current browser to do the work and checks the actual result instead of trusting a browser name or version.
| Format | Input | Decode path | Output | Important limit | Evidence |
|---|---|---|---|---|---|
| JPEG.jpg · .jpeg | Available | Browser-native image decoder. | Runtime-dependentCanvas toBlob request for image/jpeg; returned MIME type is checked. | JPEG output is lossy and transparent pixels require a chosen solid background. | |
| PNG.png | Available | Browser-native image decoder. | AvailableCanvas toBlob request for image/png; returned MIME type is checked. | PNG is lossless, so photographic output can be much larger than JPEG or WebP. | |
| WebP.webp | Runtime-dependent | Browser-native image decoder. | Runtime-dependentCanvas toBlob request for image/webp; silent PNG fallback is rejected. | Encoding quality and file size vary by browser implementation and source content. | |
| AVIF.avif | Runtime-dependent | Browser-native image decoder only; there is no bundled AVIF fallback decoder. | Not offered | A browser that cannot decode the selected AVIF file cannot use it in FormatTailor. | |
| HEIC / HEIF.heic · .heif | Runtime-dependent | Try the browser decoder first, then the locally loaded heic2any decoder. | Not offered | FormatTailor exports one decoded image; sequences, depth information, and unsupported variants may not survive or may fail to decode. |
Interface limit before decoding starts.
Maximum width or height for a decoded source.
Maximum decoded pixel area.
Maximum requested width or height.
Privacy boundary
FormatTailor's static pages still need normal network requests. The distinction is whether the selected image bytes are sent to a FormatTailor processing endpoint.
The browser gives the current tab a File. FormatTailor creates local blob URLs for previews.
The tab tries createImageBitmap, then a local <img> path. HEIC/HEIF can load the bundled fallback decoder.
Decoded pixels are drawn to a two-dimensional canvas. Size and pixel-count limits are checked in the processing layer.
canvas.toBlob() creates the result. The requested MIME type is compared with the Blob's actual type before download.
What this review supports
The reviewed interface passes the selected file into browser APIs and locally loaded JavaScript. Its Astro production build is static and contains no upload handler for these tools.
What it does not promise
The browser, extensions, operating system, security software, hosting network, and eventual destination can still observe activity. Use a trusted device and independently inspect high-risk files.
Expected website traffic
HTML, CSS, JavaScript, icons, and a lazily loaded HEIC decoder can create requests. Hosting logs can receive ordinary request information such as IP address, path, time, and user agent.
Reproducible check
This is a practical check, not a substitute for a professional security audit. Use a disposable, non-sensitive test image.
Open the browser's developer tools and select the Network panel.
Reload the chosen tool page, wait for it to settle, and clear the request list.
Select and process a throwaway JPEG or PNG. For HEIC, expect a JavaScript decoder chunk to load on first use.
Inspect new requests, including Fetch/XHR and request payloads. The test image bytes should not appear in a request to FormatTailor.
Repeat after a site release or browser update. Record the page URL, date, browser build, and observed request paths.
Machine-readable data
The JSON includes the methodology, safety limits, format rows, status definitions, and source registry. The CSV is a flat format table for spreadsheets. Both carry the same review date.
Suggested citation: “FormatTailor browser image-format capability map, version 1.0.0, reviewed 2026-08-21.” Link to this page so readers also receive the limitations and source notes.
Evidence register
Format standards establish what a format can represent. Browser support still changes, so the dataset points to maintained compatibility data and labels runtime-dependent paths honestly.
src/components/ToolWorkspace.tsx, src/lib/image.ts, src/lib/format.ts, package-lock.json. Dependency repositories document what the included libraries aim to handle; they are not evidence that every source file will succeed.