JPG to PDF, Without Re-compressing
The JPEG bytes are copied into the PDF as they are — no second generation of loss.
Why this conversion can be lossless
PDF has a filter called /DCTDecode that accepts a JPEG bitstream verbatim. The PDF reader hands those bytes to a JPEG decoder and draws the result. So a JPEG can be packaged into a PDF with no pixels re-encoded and no quality lost — the file grows by a few hundred bytes of document structure and that is all. This is why many online converters produce a JPG-to-PDF output almost identical in size to the input, and why any converter that produces a dramatically larger or smaller file is doing something else.
Page size choices, and what each does to the image
- A4, Letter, Legal, A5 — the image is scaled to fit inside the margin box, preserving its aspect ratio, and centred on the page. Nothing is cropped. A 3:2 photo on A4 becomes a landscape band with white space above and below.
- Fit to image — the page is created at exactly the image's pixel dimensions converted to points, producing a PDF page with no margins at all. This is the archiving choice: the document is a faithful wrapper around the picture.
- Margin — measured in points, where 72 points make an inch. A 36-point margin is half an inch. Set it to zero with 'fit to image' for an edge-to-edge page.
Aspect ratio is never sacrificed
Many naive converters stretch an image to fill a fixed page, which distorts faces and circles into ellipses. This one scales uniformly and centres the result, so the only variable is how much white space surrounds the picture. If you need the image to fill the page exactly, resize it to the page's aspect ratio first — a 1:1.414 rectangle for A4 — and then convert with a zero margin.
When one page is not what you want
A multi-page document built from a stack of photographs — a scanned contract, a set of receipts, a portfolio — is better served by the images-to-PDF tool, which takes the whole set at once and produces one page per image in the order you choose. Converting each file separately and then looking for a merge tool is more work and produces the same result with more opportunities for the pages to end up out of sequence.
The output has no text layer. Whatever letters are visible in the picture are pixels, so the PDF is not searchable. For photographs that is irrelevant; for scans of documents it is the main limitation, and it is a property of image-based PDFs rather than of this tool.
How to use it
- Drop a JPG, or paste one.
- Choose a page size — or 'fit to image' for an exact wrapper.
- Set the margin if you are using a fixed page size.
- Convert and open the result to confirm the orientation.
Worth knowing
- JPEG is embedded with DCTDecode, so no pixels are re-encoded.
- A PDF point is 1/72 inch; 72 points equals one inch.
- 'Fit to image' produces a page matching the image's own dimensions.
- Scaling always preserves the aspect ratio — no stretching occurs.
Limitations
- Only one image per document; use the multi-image tool for more.
- No text layer, so the result is not searchable.
- PNG and WebP input must be converted to JPEG first, which is lossy.
- The produced PDF cannot be edited afterwards.