Why combine images into a PDF at all
Because one file is easier to handle than twelve. Application portals usually accept a single document, printers keep the pages in order, and email attachments stay tidy. A PDF also fixes the page order and orientation, which a folder of loose photos does not.
The common jobs: scanned documents photographed page by page, receipts for an expense claim, ID and supporting paperwork for an application, and portfolios where the order is the point.
No quality is lost when JPGs go into a PDF
This surprises people, and it is worth understanding. A PDF can store a JPEG exactly as it is — the bytes go in untouched, tagged as DCTDecode, and the reader decodes the original image. There is no re-compression step, so nothing degrades.
The practical consequence is that your PDF will be roughly the size of your images added together. If it comes out larger than you need, compress the images before combining them rather than looking for a way to shrink the PDF afterwards — the compress to an exact KB size tool does that.
Choosing a page size
A4 is the right default almost everywhere outside North America, and US Letter inside it. Both put your image on a standard page with the aspect ratio preserved, which is what you want for anything that will be printed or filed.
Fit to image makes each page exactly the dimensions of the photo on it. There are no borders and pages may vary in size, which is ideal for screenshots, scanned receipts and anything viewed on screen rather than printed.
Auto orientation decides per image: a landscape photo gets a landscape page, a portrait one gets portrait. Force portrait or landscape if you need every page to match, for example when the PDF is being bound or printed double-sided.
Order matters, and you control it
Files are added in the order you select them, which is rarely the order you want. Drag any thumbnail to move it, and the page numbers update as you go. Get this right before you create the PDF — reordering pages afterwards needs a separate editor.
A tip for scanned documents: name the files 01, 02, 03 before you select them and most browsers will hand them over in that order to begin with.
Why nothing is uploaded
The PDF is assembled in your browser using JavaScript, and the file is handed straight back to you as a download. Your images never reach a server, there is no queue, no size limit imposed by someone else’s upload form, and nothing to delete afterwards.
This tool also loads no third-party library. Many browser-based PDF tools pull in a large PDF library from a CDN, which means a request to another company every time the page opens. This one does not — the PDF writer is a few hundred lines of plain JavaScript served from this site. Open your browser’s network tab while you build a PDF and you will see no request at all from the tool. (You will see the theme load its fonts, which is a separate thing and nothing to do with your files.)
That matters here more than on most tools, because the documents people combine into PDFs are overwhelmingly personal — passports, bank statements, certificates, medical letters.
Questions people ask
Is there a limit on how many images?
A hundred per PDF, which is a limit of practicality rather than technology. Very large batches use a lot of memory in the browser and produce a file most systems will reject anyway. For more than that, build it in two parts.
Can I add PNG or WebP images?
Yes. PDF has no native slot for those formats, so they are converted to JPEG first at high quality — the only step in this tool where anything is re-encoded. If you need a lossless result, keep the images as they are and use a different route.
Why is my PDF so large?
Because it contains your images at full size. Ten 4 MB photos make a 40 MB PDF. Compress or resize the images first with compress to an exact KB size or the image converter.
Will the PDF work everywhere?
It is a standard PDF 1.4 document and opens in Acrobat, Preview, Chrome, Edge and every mobile reader. There is no encryption, no password and no unusual feature that an older reader might choke on.
Can I convert the other way, PDF to JPG?
Yes — PDF to JPG renders every page of a document as an image. It is a genuinely different job under the hood: writing a PDF means wrapping your images in a container, while reading one means running the drawing instructions inside it. The two tools share no code.