JFIF to PNG Converter

How it works

A JFIF to PNG converter is what people open when Windows Photos or a camera export saved a JPEG as .jfif and a form, CMS, or printer wants PNG. Renaming the extension does not add a PNG chunk. This page stays in the tab.

1. Drop JFIF files — .jfif, .jif, .jpe, .jpg, or .jpeg. Up to eight files, 15MB each. Nothing is uploaded.
2. Read the APP0 marker — the tool parses JFIF version, density units (DPI or dots/cm), X/Y density, and whether an EXIF APP1 is also present. That report is the proof this is not a rename.
3. Write a real PNG — pixels are decoded in the browser. If you keep print density, a pHYs chunk is injected after IHDR so the PNG still knows 300 DPI (or whatever the JFIF tagged). Strip mode leaves density out for web uploads.
4. Download — PNG for the selected file, or a ZIP of the batch. Copy a one-line report if you need to log version and density.

This is not a generic JPG compressor and not the DPI checker that exports JPEG. The product is a JFIF to PNG converter that preserves print density in the PNG.

FAQ

Is a .jfif just a JPEG?

Yes. JFIF is the JPEG File Interchange Format. Windows often writes .jfif instead of .jpg. Other apps still expect PNG. This JFIF to PNG converter decodes the JPEG and writes PNG bytes.

Why keep density?

Print shops and some layout tools read PNG pHYs. A canvas export usually drops it. Preserve mode copies JFIF APP0 density into that chunk so a 300 DPI scan does not become a 72 DPI web PNG.

Do you upload my photos?

No. Parse, decode, PNG encode, pHYs inject, and ZIP all run in the browser. Close the tab and the bytes are gone.

What if the file has no JFIF marker?

Some cameras write EXIF-only JPEGs. The converter still makes a PNG. Density is left off unless a JFIF APP0 was present — we do not invent a DPI tag.

Why did a huge photo shrink?

Edges over 4096px are scaled so getImageData stays usable. The size line marks those files as scaled.