FILEFIX / FORMAT GUIDE
Choose the right file format
A practical reference for preparing images, scans and documents. Choose by what must survive the conversion—not just the filename.
Start with the receiving requirements
Write down the accepted extension, maximum byte count, pixel dimensions and page limit before editing. A portal may accept JPEG but reject a valid JPEG that is too large. Renaming photo.png to photo.jpg changes the name, not the encoding. A MIME type is a registered label; it is not proof that a file is valid or safe.
Use image compression to a measured KB limit for a byte target and image resizing for pixel dimensions. FileFix uses decimal KB: 200 KB means 200,000 bytes. Keep the original and inspect the new copy.
Compare the supported formats
| Format | Input | Output | What to expect |
|---|---|---|---|
| image/jpeg .jpg, .jpeg | Yes | Yes | Photographs. JPEG output uses a white background and lossy compression. Open tool ↗ |
| image/png .png | Yes | Yes | Transparency and crisp graphics. Use the PNG optimizer to preserve decoded pixels. Open tool ↗ |
| image/webp .webp | Yes | Yes | Browser-encoded image output with transparency. Encoding depends on browser support. Open tool ↗ |
| image/heic .heic | Yes | No | One standard image is decoded to 8-bit RGBA. HDR and color-profile fidelity are not guaranteed. Open tool ↗ |
| image/heif .heif | Yes | No | Supported HEIF/HEIC brands only. Single-image input; no HEIF export. Open tool ↗ |
| image/tiff .tif, .tiff | Yes | No | Single-page supported TIFF profiles. Multipage and unsupported profiles are rejected. Open tool ↗ |
| application/pdf | Yes | Yes | Page tools, overlays, compression and OCR. Signed/encrypted/XFA PDFs are rejected. Fill fields in the form tool; image compression can preserve AcroForms. Open tool ↗ |
| application/zip .zip | No | Yes | Download completed batch outputs and a report together. ZIP input extraction is not offered. Open tool ↗ |
| application/json .json | Yes | Yes | Requirement-preset import/export and measured reports only. Arbitrary JSON is not converted. Open tool ↗ |
| text/plain .txt | No | Yes | Recognized OCR text. Review words, punctuation and reading order. Open tool ↗ |
| text/html .html | No | Yes | Optional standalone check sheet. A PDF check sheet is also available. Open tool ↗ |
Choose the right kind of PDF compression
Lossless optimization: try it when text and vector artwork should remain intact. It may save little if the document is already optimized. Image compression: recompress supported embedded images; inspect small text and diagrams after changing quality. Scan reduction: rebuild pages as images when a smaller scan is the priority. It removes existing searchable text; it is not equivalent to lossless optimization.
Choose lossless PDF optimization, embedded-image compression or scan reduction. To add a searchable layer, use OCR and review spelling, punctuation and reading order.
Check what a conversion can change
JPEG is lossy and does not preserve transparency. Repeatedly saving a JPEG can accumulate damage, so work from an original. PNG is useful for transparency and crisp graphics, although it can be large for photographs. WebP output depends on the browser encoder. Single-image HEIC/HEIF and supported TIFF input can be decoded, but HDR, color profiles and multipage behavior are not guaranteed.
Canvas-based image conversion creates a new pixel encoding and does not deliberately copy EXIF. That is not a forensic metadata-removal guarantee. Ordinary PDF merging and overlays do not erase hidden content. Use the dedicated raster redaction workflow when its documented trade-off is appropriate, and review the exported document before sharing it.
A reliable upload checklist
- Keep an untouched original.
- Check the receiving service’s accepted format and exact limits.
- Choose the tool that preserves the content you need.
- Inspect the downloaded result at useful magnification; check all pages and transparent edges.
- Check the actual output byte count, dimensions and page count.
- Open the final file in the software or service that will receive it. A local pass is not a guarantee of acceptance.
All FileFix processing stays in your browser. The interactive format registry remains separate and ad-free, as do file workspaces, results and exports. Do not upload a confidential document to an unrelated converter just because its name appears in a format registry.
Sources and maintenance
The table is generated from FileFix’s implemented capability list, not inferred from registry names. The IANA media-type registry supplies format identifiers; its registry data is CC0. See the MDN image-format guide for browser context. Capabilities reviewed 5 October 2026. Report a correction through Help.