Image to PDF Converter

About Image to PDF Converter

How to Use the Converter

Step	Action
1. Upload images	Drag and drop files onto the upload area, or click to browse
2. Arrange order	Use the up/down buttons to reorder pages
3. Choose page size	Select A4, US Letter, or Fit to Image
4. Set orientation	Portrait, Landscape, or Auto (best fit per image)
5. Generate PDF	Uses the browser's Save as PDF via the print dialog

The converter opens a new window with images laid out one per page, then triggers the browser's native print dialog. Select "Save as PDF" as the destination (not a physical printer) to download the finished file. Chrome, Edge, Firefox, and Safari all support this method natively.

Page Size Options

Page Size	Dimensions	Best For
A4	210 x 297 mm (8.27 x 11.69 in)	Standard documents, European/international printing
US Letter	216 x 279 mm (8.5 x 11 in)	North American standard, US and Canadian printing
Fit to Image	Matches each image's dimensions	Photo portfolios, screenshots, preserving exact aspect ratios

A4 is the international standard defined by ISO 216 and used in most countries outside North America. US Letter is slightly wider and shorter. "Fit to Image" mode sizes each page to match the image exactly, removing all margins and white space. This works well for photo collections or screenshots where the image should fill the entire page.

Understanding Image Resolution and Print Quality

The quality of a printed PDF depends on the resolution of the source images. Resolution is measured in DPI (dots per inch) - the number of pixels per physical inch when printed.

DPI	Quality Level	Typical Use
72 DPI	Screen only	Web images, social media downloads - will look pixelated if printed
150 DPI	Acceptable	Drafts, internal documents, reference prints
300 DPI	Professional	Professional printing, portfolios, client-facing documents
600 DPI	High detail	Fine art reproduction, detailed technical drawings

A standard 12-megapixel smartphone photo (4000 x 3000 pixels) prints at roughly 300 DPI on a 13 x 10 inch area, which covers an A4 page well. A web screenshot at 1920 x 1080 pixels only manages about 150 DPI on A4 - fine for reference but not sharp enough for professional printing. Keep in mind that upscaling a low-resolution image to a larger size does not improve quality; the output can only be as good as the source.

Typical Image File Sizes and PDF Output

The final PDF size depends almost entirely on the images inside it, since each image is embedded at its original resolution. Here is a rough guide to expected file sizes.

Source	Typical Size Per Image	10-Page PDF
Smartphone JPEG (12 MP)	2 - 5 MB	20 - 50 MB
DSLR JPEG (24 MP)	5 - 10 MB	50 - 100 MB
Screenshot PNG (1080p)	0.5 - 2 MB	5 - 20 MB
Web image (compressed)	50 - 200 KB	0.5 - 2 MB
Scanned document (300 DPI A4)	1 - 4 MB	10 - 40 MB

If the resulting PDF is too large to email (most providers cap attachments at 25 MB), compress the source images first using the image compressor. Reducing JPEG quality from 95% to 80% can cut file size by 60-70% with minimal visible difference.

Common Use Cases

Use Case	Recommended Settings	Tips
Scanned receipts / documents	A4, Portrait, order by date	Compress images first to keep the PDF under 25 MB for email
Photo portfolio	Fit to Image or A4 Landscape	Consistent image dimensions give the cleanest layout
Screenshot sequence	Fit to Image, order by step number	Useful for documentation, tutorials, bug reports
Reference images for a project	A4, Auto orientation	Mix of portrait and landscape images handled automatically
Printable photo album	A4, Auto orientation	One image per page, add margins in the print dialog
Insurance or legal evidence	A4, Portrait	Keeps images in a single paginated file for submissions

Image Format Support

Format	Supported	Notes
JPEG (.jpg, .jpeg)	Yes	Most common - photos from cameras and phones
PNG (.png)	Yes	Screenshots, graphics with transparency
WebP (.webp)	Yes	Modern web format, good compression
GIF (.gif)	Yes (first frame)	Only the first frame of animated GIFs is used
BMP (.bmp)	Yes	Uncompressed, results in larger PDFs
SVG (.svg)	No	Vector format - rasterised formats only

JPEG is the best choice for photographs because it uses lossy compression that keeps file sizes small. PNG is better for screenshots, diagrams, and graphics with sharp edges or text, since it uses lossless compression that preserves every pixel. WebP offers roughly 25-30% smaller files than JPEG at equivalent quality, making it a good option for web-sourced images. If starting with BMP files, consider converting to JPEG or PNG first to avoid unnecessarily large PDFs.

Tips for Smaller, Sharper PDFs

Tip	Why It Matters
Compress large images before converting	A PDF with ten 5 MB photos will be 50+ MB - hard to email or share
Use consistent image dimensions	Mixed sizes look uneven in the PDF layout
Crop images to remove unnecessary borders	Cleaner pages, especially for scanned documents
Check the preview before generating	Verify page order and orientation are correct
Use Auto orientation for mixed content	Automatically picks portrait or landscape per image for best fit
Match resolution to purpose	300 DPI for printing, 150 DPI for screen-only viewing

For scanned documents, many scanner apps save images at 200-300 DPI by default, which is fine for most purposes. If scanning specifically for archival, 300 DPI grayscale or colour at JPEG quality 90+ gives a good balance between clarity and file size.

PDF vs Other Multi-Image Formats

Format	Best For	Advantages	Limitations
PDF	Documents, printing, sharing	Universal, printable, page-based, mixed orientations	Not editable, images embedded (large files)
ZIP archive	Sending multiple images	Preserves originals, smaller than PDF	Recipient must extract, no inline preview
Multi-page TIFF	Scanning, archival	Lossless, industry standard for scans	Limited viewer support, very large files
DOCX	Reports with text and images	Editable, supports mixed content	Layout shifts between viewers, not fixed

PDF is the most widely used document format globally, with over 290 billion new PDFs created each year according to PDF Reader Pro research. The format is standardised as ISO 32000, meaning any compliant viewer renders pages identically regardless of operating system or device. That makes it the safest choice for sharing image collections where consistent layout matters.

How the Browser Print-to-PDF Method Works

This converter uses the browser's built-in print engine rather than a JavaScript PDF library. When the generate button is clicked, a new browser tab opens with the images arranged in a print-ready HTML layout. The browser then triggers its native print dialog, where "Save as PDF" can be selected as the output destination. This approach has several advantages: no external library is downloaded, the browser's own rendering engine handles image scaling and page breaks, and the resulting PDF matches exactly what appears in the print preview. The trade-off is that the print dialog itself varies slightly between browsers - Chrome and Edge show a clean sidebar, Firefox uses a toolbar at the top, and Safari opens a sheet from the title bar.

Troubleshooting Common Issues

Problem	Cause	Solution
New window blocked	Browser popup blocker	Allow popups for this site, or use Ctrl/Cmd+click if prompted
Images look blurry in PDF	Low-resolution source images	Use higher-resolution originals (300 DPI for print, 150 DPI minimum)
PDF file is very large	High-resolution or uncompressed images	Compress images before converting, or use JPEG instead of PNG for photos
White borders around images	Page size larger than image	Switch to "Fit to Image" mode, or crop images to match the page aspect ratio
Wrong page order	Images not reordered before generating	Use the up/down arrow buttons to arrange pages before clicking Generate
Image cut off at edges	Image aspect ratio does not match page	Use Auto orientation, or crop the image to 3:4 ratio for portrait A4

How Many Images Can the Browser Handle?

Since all processing happens in the browser, practical limits depend on available system memory. Each image is held in memory as a decoded bitmap while the print layout is generated. A rough rule of thumb: each megapixel of image data uses about 4 MB of RAM when decoded (width x height x 4 bytes per RGBA pixel). A 12 MP smartphone photo takes roughly 48 MB of RAM when fully decoded, so 20 such photos would need about 960 MB. Modern browsers on devices with 8+ GB of RAM can usually handle 30-50 smartphone photos without issues. For larger batches, split the images into groups and generate multiple PDFs, then combine them using the PDF merge tool.

Privacy and Security

All processing happens entirely in the browser. Images are loaded into memory using object URLs (blob references) and never transmitted over the network. The converter does not use any external API, cloud service, or server-side processing. This makes it safe for sensitive documents like medical records, financial statements, identity documents, or legal evidence. Once the browser tab is closed, the image data is released from memory. No cookies or tracking are associated with the conversion - the tool runs as pure client-side JavaScript with zero network requests.

Need to resize images before converting? Use the image resizer to adjust dimensions, or the image compressor to reduce file sizes first. To combine existing PDF files rather than images, try the PDF merge tool instead.

Sources

• ISO 32000-2:2020 - Portable Document Format (PDF 2.0)
• PDF Reader Pro - PDF Market Growth Statistics 2025
• PrintingForLess - Standard DPI and Image Resolution for Printing