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yutils
Usage / FAQ

When to use

  • Bundle scanned document pages into one PDF for sharing or archiving
  • Turn photos of receipts or invoices into a single PDF for expense reports
  • Collect snapshots from a trip or event into a printable photo album
  • Assemble design or artwork images into a portfolio PDF
  • Stitch several screenshots into one document instead of attaching them one by one

FAQ

Q.Are my images recompressed or downgraded?
A.JPEG and PNG files are embedded as-is, with no re-encoding — so quality is unchanged. Other formats (WebP, GIF, BMP) are converted to PNG once before embedding, which is also lossless. With the 'Fit image' page size, each page matches the original pixel dimensions exactly.
Q.Can I change the page order?
A.Yes. Use the up/down buttons on each image to reorder them. Pages appear in the PDF in the order shown in the list, top to bottom.
Q.How do margins and A4 / Letter fitting work?
A.Pick A4 or Letter to place each image on a fixed-size page; orientation can be Auto (matches the image), Portrait, or Landscape. The image is scaled to fit inside the margins while keeping its aspect ratio, then centered. 'Fit image' ignores paper size and makes each page exactly the image's size with no margins.
Q.Are my files uploaded to a server?
A.No. The whole conversion runs in your browser with pdf-lib — images never leave your device. That keeps scans, receipts, and personal photos private.
Fun facts

  • A JPEG can be dropped into a PDF without re-encoding. PDF's DCTDecode filter understands JPEG's compressed stream directly, so the original bytes are stored as-is — that's why placing a JPEG into a PDF loses no quality and barely grows the file.

    Wikipedia — JPEG

  • The A4 page (210 × 297 mm) comes from ISO 216, whose sheets all share a 1:√2 aspect ratio. Halving an A4 along its long edge gives two A5 sheets of the exact same proportions — which is why scaling between A-series sizes never distorts the layout.

    Wikipedia — ISO 216

  • PDF descends from Adobe's PostScript page-description language, so a PDF page is a fixed physical canvas measured in points (1 pt = 1/72 inch), not a stretchy web layout. That's exactly why image-to-PDF tools ask you to choose a page size and orientation.

    Wikipedia — PostScript

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