How the PDF is made
A .jfif file is a JPEG, and the PDF format can store
JPEG data exactly as it is — a PDF page can reference a JPEG stream
directly rather than needing its own pixel format. So for an ordinary
JFIF or JPG, this tool reads the image's size and colour components
straight from the file and places the original bytes into the PDF
page without decoding or compressing them again. The picture in the
PDF is the same picture you started with, byte for byte, and the
results list marks those files as original JPEG kept.
Some images cannot be copied across that way and are re-encoded instead. Phone photos often store their rotation as an EXIF flag rather than actually rotating the pixels, and PDF viewers ignore that flag — copied as-is, they would appear sideways or upside down. Those photos, CMYK JPEGs (a colour mode common in print files that a PDF viewer would render incorrectly if embedded raw), and PNG, WebP, GIF and BMP files are decoded by your browser first, drawn the right way up, and saved as JPEG at the quality you choose before going into the PDF. The results list shows which path each file took, so you can see whether a given image was kept exactly or rebuilt.
Page size and orientation
Same size as the image makes each PDF page exactly as large as its picture, measured in the image's own pixels treated as points, with no margins and no scaling — the most faithful option for viewing on screen, since nothing about the picture is altered to fit a fixed sheet. A4 puts each image on a standard A4 sheet with margins, ready for printing: a wide image gets a landscape page and a tall one gets a portrait page, chosen automatically from its proportions, and each image is scaled down to fit within the margins and centred. A small image is never stretched beyond its own size to fill the page — doing that would make it look blurry for no reason.
One PDF or many
Every converted image gets its own single-page PDF by default, which you can download individually or together in a ZIP if you have converted several. Once two or more images have been converted, a "Download as one PDF" button also appears: it builds a single PDF with one image per page, in the same order the files are listed in the queue. The page-size choice you made applies to that combined PDF too, so a scanned multi-page document converts into one file with consistent pages rather than needing to be assembled by hand afterwards.
Common mistakes
Expecting the PDF text to be selectable is the most common misunderstanding: this tool places images into PDF pages, it does not recognise or embed any text, so a photographed document becomes a PDF you can view and print but not search or copy text from. For that you would need a separate OCR step, which this page does not do. A second trap is assuming re-encoding always happens — for a straight, correctly oriented JFIF or JPG it usually does not, and forcing a re-encode you did not need only costs quality for nothing.
If you only need a .jpg or .png rather than
a PDF, converting straight to those with
JFIF to JPG or
JFIF to PNG skips
the extra step. If your images are already in a Word document you are
building rather than a standalone PDF, see
Image to Word
instead.
Edge cases
A JPEG with an unusual colour encoding — CMYK rather than the common RGB, which turns up in some files exported from print-design software — cannot be embedded directly, because PDF viewers do not reliably render CMYK JPEG data the way image editors do. It is decoded and re-encoded as RGB JPEG instead, which is why it takes the re-encoded path even though it started out as a perfectly valid JPEG. A file that fails to decode at all — genuinely corrupted, or not really an image despite its extension — is rejected with a plain message rather than producing a PDF page with nothing useful on it.
Where your images go
Nowhere. The PDF is assembled in your browser by a small script on this page — the same one that reads the JPEG header and writes the PDF structure — and the site has no upload endpoint for images. Your original files are not modified; only new PDF files are produced for you to download.
Limits
Up to 30 images of 25 MB each per batch, checked before conversion starts. The PDF holds images only — there is no text recognition, so text in a photographed page cannot be searched or selected, and tables, forms or any structure in the original document are not reconstructed. Transparent areas in a PNG or WebP become white, because JPEG (the format used inside the PDF) has no transparency. Animated GIFs contribute only their first frame to the page.