Combining photos into a PDF: page size, margins, and the JPG-passthrough trick
Practical tips for turning a folder of photos into a clean PDF. Why margins matter, how 'Fit' differs from A4, and what to do when your images are different sizes.
You have a folder of photos and you need to send them as a single PDF. Maybe they’re receipts for an expense report, scanned documents your phone captured, or pages of a notebook. Whichever it is, the conversion is straightforward — if you understand three settings that most tools bury and don’t explain.
This post covers what those settings actually do and how to pick the right one for your situation.
The three knobs that matter
Every “JPG to PDF” tool exposes some version of these:
- Page size — what physical page the image sits on.
- Orientation — portrait or landscape.
- Margin — whitespace around the image.
How you set these determines whether the output looks like a clean document or like a photo dropped on the wrong-sized page.
Page size: Fit vs. fixed
The hardest setting to grasp is Fit. It means: “make the page exactly the dimensions of the image.” Not “shrink the image to fit a page” — the opposite.
| Setting | What happens |
|---|---|
| Fit | Page = image’s pixel dimensions (1px = 1pt). No whitespace, no scaling. Perfect for receipts. |
| A4 | Standard A4 page (210 × 297 mm). Image fits inside with optional margin. Best for documents. |
| US Letter | Standard 8.5 × 11 inches. Same idea as A4 for US-format documents. |
When to use Fit: receipts, scanned notes, photos where the image is the document. The PDF wraps the image with zero extra space.
When to use A4 or Letter: anything that should look “document-like” — a portfolio, a report, photos with whitespace around them. The PDF has consistent page dimensions regardless of image aspect ratio.
The trap: many people pick A4 by default because that’s “what PDFs are.” For receipts, that’s wrong — you end up with a tiny receipt floating in a sea of white space. Pick Fit.
Margins
In Fit mode, margin adds whitespace around the image (the page grows). In A4/Letter, margin is inside the page (the image shrinks).
| Margin | Use case |
|---|---|
| No margin | Receipts, scans, photos that should fill the page. Default if you’re not sure. |
| Small | Mild padding — looks “designed” without losing screen space. |
| Big | Photo books, portraits with framing whitespace. |
What about different-sized images?
If you’re combining a 4000×3000 photo with a 800×600 screenshot, you have two choices:
- Fit mode: pages will vary in size. Each photo gets its own page-size match. This looks weird if you flip through.
- A4/Letter: every page is the same size. Each image fits inside according to its aspect ratio, with margin. Looks consistent.
For mixed-content PDFs, A4 + Small margin is the safe default.
JPEG passthrough — what it means for quality
Here’s a detail that matters: when our JPG to PDF tool embeds a JPEG, the JPEG bytes are passed through to the PDF verbatim. No re-encoding, no quality loss. The PDF size ≈ the JPEG size.
For PNGs it’s different — PNG isn’t a native PDF image format, so PNGs are decoded and re-embedded. Smaller PNGs (logos, simple graphics) stay small. Big PNGs with photographic content can balloon to multiple MB in the PDF. If your PNG is essentially a photo, convert it to JPEG first.
Rotation, sorting, and removing tiles
The other settings on JPG to PDF:
- Drag tiles to reorder.
- Sort A–Z to sort by filename alphabetically (numeric-aware:
photo-2.jpgcomes beforephoto-10.jpg). - Hover any tile to reveal rotate and remove buttons.
- Merge all images in one PDF file (default) vs. uncheck for a ZIP with one PDF per image.
The live preview shows exactly what the final page will look like — page frame, margin, and rotation all reflected before you hit Convert.
After the conversion
If your photos are large and the PDF comes out bigger than you want, run it through Compress PDF at the Recommended level. JPEG-heavy PDFs typically shrink 30–60% with no visible quality loss because the source photos were captured at higher resolution than you’ll ever view them at.
Privacy
Images are read and embedded locally, and the result downloaded — all in your browser tab. Nothing is uploaded. For receipts and personal photos especially, that should be the default everywhere.
Try JPG to PDF and see the live page-frame preview in action.