Docify

By Docify

Images to PDF Limits: Not a Merger or Collage

• 4 min read

Docify's Images to PDF page is a thin browser wrapper around jsPDF: one image per A4 portrait page, addImage always passed as JPEG, fitted minus 20 mm and centered. It is not a PDF merger, collage, OCR tool, or compressor. Landscape photos stay on a portrait page. Many SVG and HEIC files fail at generate time with alert().

The slug says “merge,” but the live Images to PDF tool only concatenates bitmaps. It does not open an existing PDF. For the generate pipeline, see convert JPG to PDF with jsPDF. For Up / Down page order, see combining several images.

What developers get

  • new jsPDF() defaults (A4 portrait, millimetres). No orientation toggle.
  • Pixel size from an HTML Image onload of the data URL — not EXIF, not a decoder you configure.
  • addImage(dataUrl, 'JPEG', x, y, width, height) on the original data URL, including PNG sources. There is no format picker.
  • Download name is always images.pdf. Generate errors use alert(), not an in-page error card.

What this page will not do

  • Merge or split PDFs. There is no application/pdf picker here (that belongs to the PDF signer, which stamps page 1 only).
  • Place several photos on one page, add captions, or run OCR.
  • Rotate the page to landscape, set margins other than the 20 mm fit, or password-protect the file.
  • Shrink attachments. Wrapping images in a PDF is not advertised as a size win.

Generate images.pdf locally

One image per A4 page. Not a PDF merger. Files stay on the device.

Use Images to PDF →

FAQ

Can I merge existing PDFs?
No. The picker is image/* only. There is no PDF upload, no page extract, and no concatenate-PDFs path. Generate PDF writes one image per A4 page, addImage always passed as JPEG, and saves images.pdf.
Does a landscape photo rotate the page?
No. jsPDF stays A4 portrait. A wide bitmap is fitted to page width minus 20 mm and centered, so the extra space is top and bottom. The page itself is never rotated.
Why do some files fail at generate time?
Upload only checks that MIME type starts with image/ and stores a data URL. Preview uses an img tag. Embed always calls addImage with the JPEG format argument on that same data URL. Types the browser or jsPDF cannot decode (many SVG or HEIC files) throw; the page shows alert("Error generating PDF: " + error.message).
Does wrapping images in a PDF shrink the download?
Not as a feature. There is no compressor, no DPI control, and no “space saving” pass. jsPDF writes images.pdf, addImage always passed as JPEG. The old “reduce email attachment size” claim was not about this page.

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