Images to PDF – Frequently Asked Questions

The Images to PDF tool converts multiple image files into a single, organized PDF document with customizable layouts.

Key Features:

• Multiple Layouts: Choose 1, 2, 4, 6, or 9 images per page
• Drag-and-Drop Reordering: Rearrange images in any order
• Thumbnail Size Control: Adjust preview size (Small to X-Large)
• Live PDF Preview: See exactly how your PDF will look
• Grid Layouts: Automatic grid arrangement with proper spacing
• Multiple Formats: Supports JPG, PNG, GIF, BMP, WEBP

Use Cases:

• Create photo albums from image collections
• Build professional portfolios with multiple images per page
• Compile product catalogs with grid layouts
• Organize scanned documents into multi-page PDFs
• Create presentation handouts with image grids

The tool supports all common image formats:

• JPG/JPEG: Most common photo format
• PNG: Supports transparency (converted to white background in PDF)
• GIF: Animated GIFs show as static first frame
• BMP: Windows bitmap format
• WEBP: Modern web image format

Format Mixing:

• You can combine different formats in the same PDF
• Example: Upload 3 JPGs + 2 PNGs + 1 GIF = 6-page PDF
• All images are optimized during conversion

Technical Details:

• Images are converted to JPEG for embedding in PDF
• Maximum image dimension optimized to 1920 pixels
• Aspect ratios always maintained
• Quality preserved at 90% JPEG compression

You can choose from 5 different layout options:

1. One Image Per Page (Full Page)

• Single image fills entire page
• Best for: Large photos, posters, high-detail images
• Grid: 1×1

2. Two Images Per Page (Side by Side)

• Two images placed horizontally
• Best for: Before/after comparisons, paired images
• Grid: 2×1 (2 columns, 1 row)

3. Four Images Per Page (2×2 Grid)

• Four images in a square grid
• Best for: Photo collections, product catalogs
• Grid: 2×2 (2 columns, 2 rows)

4. Six Images Per Page (2×3 Grid)

• Six images in 2 columns, 3 rows
• Best for: Contact sheets, thumbnail galleries
• Grid: 2×3

5. Nine Images Per Page (3×3 Grid)

• Nine images in a 3×3 grid
• Best for: Large photo sets, comprehensive catalogs
• Grid: 3×3 (3 columns, 3 rows)

How to Select Layout:

1. Upload your images
2. Use the dropdown menu OR click visual grid icons
3. PDF preview updates automatically
4. Images arranged in selected grid with proper spacing

Yes! Drag-and-drop reordering is a core feature.

How to Reorder Images:

1. Upload Images: Select multiple images to upload
2. View Thumbnails: All images appear as numbered thumbnails
3. Drag to Reorder: Click and drag any thumbnail to new position
4. Numbers Update: Image numbers update to reflect new order
5. Preview Updates: PDF preview automatically refreshes

Drag-and-Drop Features:

• Visual Feedback: Dragged thumbnail follows cursor
• Drop Zones: See where image will be placed
• Smooth Animations: Other thumbnails shift smoothly
• Numbered Thumbnails: Each shows its position (1, 2, 3, etc.)

Powered by jQuery UI Sortable:

• Reliable drag-and-drop library
• Works on desktop and touch devices
• Smooth user experience

Example Workflow:

• Upload 10 images in random order
• Drag image 7 to position 1
• Drag image 3 to position 2
• All other images renumber automatically
• PDF generates with images in final order

The thumbnail size slider adjusts the size of image previews on your screen.

Size Options:

• Small (100px): See many images at once, minimal scrolling
• Medium (150px): Default size, balanced view
• Large (200px): Easier to identify images
• X-Large (250px): Maximum detail, best for visual review

Why Adjust Thumbnail Size?

• Many Images: Use smaller size to see 20+ images without scrolling
• Similar Images: Use larger size to distinguish between similar photos
• Screen Size: Adjust based on monitor (larger for big screens)
• Workflow: Small for quick overview, large for detailed review

How It Works:

1. Drag slider left/right to change size
2. Label updates (Small → Medium → Large → X-Large)
3. Thumbnails resize in real-time
4. Layout adjusts to fit more/fewer images per row

Technical Details:

• Thumbnails regenerated at new size using HTML5 Canvas
• Responsive layout adjusts to thumbnail width
• Does NOT affect final PDF quality (only preview size)

Yes! The live PDF preview is an exact representation of your final PDF.

Preview Features:

• Exact Layout: Shows images arranged in selected grid
• Correct Order: Images appear in sequence you've set
• Real PDF: Preview is actual PDF file, not a simulation
• Proper Spacing: Shows margins and padding between images
• Aspect Ratios: Images displayed with correct proportions

Auto-Update:

• Preview regenerates when you change layout (1, 2, 4, 6, or 9 per page)
• Updates when you reorder images
• Shows effect of adding or deleting images
• Debounced updates (waits 800ms after changes to avoid excessive regeneration)

What You See = What You Get:

• Preview uses same PDF generation code as final download
• Same image optimization and placement
• Same grid layout algorithm
• Same aspect ratio calculations

Preview Workflow:

1. Upload images → Preview generates first PDF
2. Change layout → Preview updates with new grid
3. Reorder images → Preview shows new order
4. When satisfied → Download matches preview exactly

No, we do not permanently store your images.

How We Handle Your Images:

• Temporary Processing: Images stored in /tmp folder only during conversion
• PDF Generation: Images converted to PDF on-demand
• Automatic Cleanup: All temporary files deleted after PDF generation
• Session Isolation: Each user's images isolated with unique identifiers
• No Database Storage: Images never saved to database

Privacy Guarantee:

• We do not access or view your images
• We do not analyze image content
• We do not share images with third parties
• All processing is temporary and secure

Security Measures:

• HTTPS Encryption: All uploads and downloads encrypted
• Server-Side Processing: No content inspection
• Temporary Files: Deleted immediately after use
• No Logging: Image filenames and content not logged

Yes, image quality is preserved during conversion.

Quality Preservation:

• High-Quality JPEG: 90% compression (excellent quality)
• Aspect Ratios: Original proportions maintained
• Resolution Optimization: Images scaled to optimal size (max 1920px)
• No Unnecessary Downscaling: Small images not artificially enlarged

Image Processing:

1. Original image loaded
2. If larger than 1920px, scaled down proportionally
3. If smaller than 1920px, kept at original size
4. Converted to JPEG at 90% quality
5. Embedded in PDF with correct dimensions

Layout Impact on Quality:

• 1 image per page: Maximum size, highest quality visibility
• 2-9 images per page: Images scaled to fit grid cells
• Quality Maintained: Even in grids, image data preserved
• Printable: PDFs suitable for printing at standard sizes

Transparency Handling:

• PNG/GIF transparency converted to white background
• Ensures images display correctly in all PDF viewers

No, there is no limit on the number of images you can convert.

Unlimited Images:

• Upload 5 images → 5-page PDF (1 per page)
• Upload 50 images → 50-page PDF or 6-page PDF (9 per page)
• Upload 100+ images → All processed into single PDF

Large Batch Handling:

• Efficient Processing: Tool handles large batches smoothly
• Auto-Pagination: Multiple pages created automatically
• Preview Performance: May take longer with 100+ images
• No Hard Limit: Process as many as your browser can handle

Examples by Layout:

• 1 per page: 50 images = 50-page PDF
• 4 per page: 50 images = 13-page PDF (12 full + 1 with 2 images)
• 9 per page: 50 images = 6-page PDF (5 full + 1 with 5 images)

Performance Tips:

• For 100+ images, consider using smaller thumbnail size
• Preview generation may take a few seconds with many images
• Final PDF generation optimized for speed

The Images to PDF tool combines modern web technologies with powerful PDF libraries.

Frontend Technologies:

• jQuery UI Sortable: Drag-and-drop reordering
  • Enables smooth thumbnail rearrangement
  • Touch-device compatible
• HTML5 Canvas: Image thumbnail generation
  • Resizes images for preview display
  • Converts to base64 for transmission
• HTML5 File API: Multiple file upload
  • input type="file" multiple
  • Handles all common image formats
• AJAX (jQuery): Asynchronous PDF generation
  • Preview generation without page reload
  • Final PDF download via blob URL

Backend Technologies (PHP):

• FPDF Library: PDF generation
  • Creates A4-sized PDF pages
  • Embeds images using Image() method
• GD Library: Image processing
  • Loads JPG, PNG, GIF, BMP, WEBP
  • Resizes and optimizes images
  • imagecopyresampled() for quality scaling
• Grid Layout Algorithm: Custom positioning
  • Calculates cell dimensions based on layout (1, 2, 4, 6, 9)
  • Places images with proper margins and padding
  • Maintains aspect ratios within cells

Processing Workflow:

1. User uploads images via file input
2. JavaScript reads files using FileReader API
3. Canvas generates thumbnails for preview
4. User reorders using jQuery UI Sortable
5. User selects layout (1-9 images per page)
6. AJAX sends images + layout to server
7. PHP processes images with GD library
8. FPDF generates PDF with grid layout:
   • Calculates grid configuration (cols × rows)
   • Computes cell dimensions with padding
   • Places each image in grid cell
   • Maintains aspect ratios
   • Creates new pages as needed
9. PDF returned as blob for download

Grid Layout Configurations:

• 1: 1×1 (1 column, 1 row)
• 2: 2×1 (2 columns, 1 row)
• 4: 2×2 (2 columns, 2 rows)
• 6: 2×3 (2 columns, 3 rows)
• 9: 3×3 (3 columns, 3 rows)