How to Combine Images into a PDF Without Stretching or Distorting
Converting photos, scanned receipts, and graphics into a consolidated PDF often results in ugly stretched images or awkward black bars. Learn the math behind aspect-ratio-preserving page fitting.
The Distortion Problem: Fixed Page Bounding Boxes
Most images have non-standard aspect ratios. A smartphone photo may have a 4:3 or 16:9 ratio, while a panoramic photo might be 21:9, and a scanned document might be approximately 1:1.414 (the square root of 2, standard for ISO paper).
When you combine these disparate images into a PDF with a fixed paper size (such as standard A4: 595.28 × 841.89 points), basic conversion tools make a critical mistake: they force the image width to equal pageWidth and the image height to equal pageHeight. This immediately stretches or squashes the image, making text unreadable and faces distorted.
The Mathematical Solution: Aspect-Preserving Containment
To render an image naturally on a PDF page without distortion, the conversion engine must calculate an aspect-ratio-locked bounding box:
Bounding Box Calculation Formula
Let available printable width be Wavail = PageWidth - 2 × Margin and printable height be Havail = PageHeight - 2 × Margin.
ImageAspect = ImageWidth / ImageHeight
PageAspect = Wavail / Havail
• If ImageAspect > PageAspect (image is wider than page):
DrawWidth = Wavail
DrawHeight = Wavail / ImageAspect
• Else (image is taller than page):
DrawHeight = Havail
DrawWidth = Havail × ImageAspect
Centering offsets: X = Margin + (Wavail - DrawWidth) / 2, Y = Margin + (Havail - DrawHeight) / 2.
Choosing Your Page Layout Options
Depending on your document's final destination, you have three primary formatting choices in FileWorks:
| Page Size Mode | Dimensions (pt) | Visual Result | Ideal Use Case |
|---|---|---|---|
| ISO A4 | 595.28 × 841.89 pt | Uniform international letterhead with clean margins. | Formal business reports, school assignments, and international submissions. |
| US Letter | 612 × 792 pt | North American standard format. | US/Canada office documentation, tax forms, and domestic filings. |
| Fit Image (Original Size) | Matches image pixels 1:1 | Each PDF page size matches the exact dimensions of that specific image. Zero margins. | Photo albums, portfolio archives, and digital comics. |
Step-by-Step: Converting Images to PDF in FileWorks
- Open the Tool: Navigate to the FileWorks Image to PDF Tool.
- Select Your Photos: Drag and drop up to 5 images (JPG, PNG, WebP, GIF, or BMP).
- Arrange the Sequence: Drag the thumbnails to arrange the exact page sequence.
-
Configure Page Layout:
- Select your paper size: A4, US Letter, or Fit to image.
- Select orientation: Portrait or Landscape.
- Select margins: No margin, Small (10 pt), or Normal (20 pt).
- Generate PDF: Click Convert to PDF. The tool compiles your images into a single vector-framed PDF directly in your browser.
Convert Your Images Now
Combine multiple JPG, PNG, or WebP images into a perfectly formatted PDF.