The conversion is trivial. The reason people redo it three times is page size, orientation and ordering — none of which most tools ask about.
Should each page match the image, or the paper?
This is the setting that decides whether the result is usable, and it is the one most converters bury.
Fit page to image makes every page exactly the dimensions of the photo it contains. Nothing is cropped and there are no margins, but the pages are all different sizes and none of them is A4. On screen this is fine. Sent to a printer it produces scaling that varies page to page.
Fit image to page puts each photo onto a standard sheet — A4 or US Letter — scaled to fit inside it. Every page is the same size and prints predictably. The cost is white space wherever the photo's proportions do not match the paper's.
- Scanned documents, receipts, ID pages, anything being printed or submitted → fit image to A4 or Letter.
- Photo albums, portfolios, screen-only sharing → fit page to image.
- Mixed portrait and landscape photos → fit to page, with auto-orientation turned on, or every landscape shot arrives sideways.
If you are outside North America, A4 is the right default. US Letter is slightly wider and shorter, and a document laid out for one and printed on the other picks up an uneven margin.
How do you keep the pages in order?
The same trap as merging: filenames sort as text, so IMG_2 lands after IMG_10. With phone photos this usually works out, because cameras pad their numbering. With manually named scans it usually does not.
Two habits fix it permanently. Pad your numbers — page-01, page-02 — so alphabetical order and reading order are the same thing. And glance at the thumbnails before exporting; a converter worth using shows them and lets you drag.
If you are scanning a multi-page document with a phone, take the photos in order in one sitting. The camera roll then carries the correct sequence by timestamp, and most tools offer to sort by date taken.
Why is the PDF so much larger than the photos?
It generally is not — the PDF is roughly the sum of the images plus a small structural overhead. What surprises people is how large the photos were to begin with. A modern phone produces 3–6 MB per shot, so twelve pages of scanned receipts is comfortably 50 MB before anything has gone wrong.
That matters because the resulting PDF then bounces off email limits and upload forms. The fix is to compress the images before conversion rather than the PDF afterwards: you get to see each image, and one lossy pass is always better than two.
For a document being read rather than printed, running the photos through the Image Compressor at quality 0.75 typically removes 70% of the weight with nothing visible lost. If the PDF already exists and is too big, Compress PDF handles it in one pass — the reasoning is covered in how to compress a PDF without losing quality.
How do you make a phone photo of a document look like a scan?
A photographed page and a scanned page are different objects, and the difference is mostly geometry and lighting rather than resolution.
A few things get you most of the way there without special software:
- Shoot straight down, not at an angle. Perspective distortion is the single biggest giveaway and the hardest thing to fix afterwards.
- Use indirect daylight rather than a flash. A direct flash produces a hot spot in the middle and shadows at the edges.
- Fill the frame with the page, then crop tight to the paper edges with the Image Cropper. Background desk is the second biggest giveaway.
- Convert with "fit image to page" onto A4 so the result matches the paper it came from.
If the recipient needs to search or copy the text, the resulting PDF will not let them — it is a photograph. Run the image through Image to Text first if the words matter more than the appearance.
Is it safe to convert ID documents and receipts online?
This is worth pausing on, because the files people most often convert to PDF are passport pages, driving licences, bank cards, medical letters and receipts for expense claims. That is close to a complete identity kit.
A conventional online converter uploads all of them to a server. Even under a good deletion policy, they exist outside your control for a window, and the value of that particular collection to an attacker is high.
A browser-based converter reads the files locally, builds the PDF in memory, and hands it back as a download — there is no upload request to make. You can verify that on any tool by opening the Network tab in developer tools before you convert. There is a fuller version of the check in are online PDF tools safe.
Frequently asked questions
What page size should I use for JPG to PDF?
A4 for most of the world, US Letter in North America, whenever the document might be printed or submitted to a form. Use "fit page to image" only for screen-only material like photo albums, where consistent paper size does not matter and you would rather avoid white margins.
Why are my landscape photos sideways in the PDF?
Auto-orientation is off, so landscape images are being placed onto portrait pages without rotating the page to match. Turn on auto-orientation, or rotate the images before converting. Some tools also mis-read the EXIF orientation flag that phones set.
How do I combine several JPGs into one PDF?
A JPG to PDF converter takes multiple files at once and makes one page per image. Confirm the order before exporting, since files are often sorted alphabetically, which puts image 10 before image 2 unless the numbers are zero-padded.
Does converting to PDF reduce image quality?
It should not. The image data is embedded as-is, so the pages look exactly like the source photos. Quality only drops if the converter re-encodes to hit a size target, which some do silently — check the output size against the sum of your inputs.
Can I make the PDF text searchable?
Not by converting alone. A photo of a page is a picture, and the PDF inherits that. You need OCR to read the characters and add a text layer. Run the images through an image-to-text tool first if searchability matters.
How do I get the PDF under an upload limit?
Compress the images before converting rather than compressing the PDF afterwards — you can see each image and it avoids two lossy passes. Quality 0.75 typically removes about 70% of the weight with nothing visible lost.