Is my image uploaded to make the PDF?

No. The PDF file is assembled byte-by-byte in your browser from the image you provide. It is never sent to any server.

How is the PDF built without a library?

The image is drawn to a canvas and exported as JPEG bytes, then embedded as a DCTDecode image object inside a minimal, spec-valid PDF (catalog, page, content stream and image XObject). The page is sized to the image at your chosen DPI.

Why is the output a JPEG inside the PDF?

JPEG (DCTDecode) is natively supported by the PDF format, keeps the file small, and works in every PDF reader. Transparent areas are flattened onto white because JPEG has no alpha channel.

How does DPI affect the page size?

The page is sized in points (1/72 inch). At 72 DPI each pixel maps to one point, so the page matches the screen size. At 150 or 300 DPI the same pixels are packed into a smaller physical area, giving a sharper print at a smaller page size.

Which DPI should I choose?

Use 72 for screen-only viewing, 150 for general documents, and 300 for high-quality printing. Higher DPI does not add detail your image lacks, but it sets the correct physical print dimensions.

Can I combine several images into one PDF?

This tool produces a single-page PDF sized to one image. To merge multiple images, convert each and then use a PDF merge tool, or place them in one image first.

Image to PDF — Gera Tools

Convert an image to PDF, privately

Wrap a photo, scan or screenshot into a single-page PDF that fits the image exactly — useful for emailing a receipt, archiving a document scan, or turning a screenshot into a printable file. Everything happens locally, so sensitive documents never leave your device.

How it works

The image is drawn onto a <canvas> and exported as JPEG bytes at your chosen quality. Those bytes are embedded as a DCTDecode image XObject inside a minimal, spec-valid PDF assembled by hand: a catalog object, a page object, a content stream that draws the image, and the image object itself. The page is sized in points (1/72 inch) from the pixel dimensions divided by the selected DPI, so the physical size is correct for screen or print. Because JPEG has no alpha channel, transparent areas are flattened onto white.

Example

A 1500×1000 px photo exported at different DPIs:

DPI	Page size (points)	Physical size
72	1500 × 1000	20.8 × 13.9 in (screen)
150	720 × 480	10 × 6.67 in
300	360 × 240	5 × 3.33 in (print)

The PDF is built entirely in your browser — the image is exported from a <canvas> and embedded directly into a minimal, valid PDF — so your file is never uploaded.