How to Convert Images to PDF (JPG, PNG, WebP — Without Uploading Them)

Turning a stack of photos or screenshots into a single PDF takes seconds. What decides whether the result is usable is where the conversion happens, which image format you start from, and three settings most people never touch.

Why convert images to PDF in your browser

Photos of a passport, a paper receipt, a signed contract or a whiteboard all arrive as images, and single images are awkward to send, print or archive. A PDF bundles them into one file with a fixed page order and a predictable page size, which is why banks, landlords, universities and government portals ask for a PDF rather than a folder of JPEG files.

The common shortcut is to drop those pictures onto a website that converts them and hands back a file. That works, but while it works your images — frequently the most personal documents you own — sit on someone else's server, get copied into their backups, and may be written into a log with your filename and IP address attached. A retention promise such as “deleted within an hour” is a statement about intent; you cannot watch it happen.

A current browser already contains the two pieces needed to do the job itself. It can decode an image, scale it and re-encode it as JPEG or PNG through the canvas API, and it can build a genuine PDF — pages, images, metadata — with JavaScript. Put the two together and the conversion never has to leave the tab. There is no temporary file to expire, no queue in someone else's storage, and nothing to hand over.

The local approach also works with a poor connection, or none at all. Once the page has loaded, you can switch off Wi-Fi and keep converting, which is a fast way to prove to yourself that no upload is taking place.

With local conversion, “your images never leave your device” is a fact about how the system is built rather than a promise about behaviour. To confirm it, open your browser's Network panel and watch while you convert: you will see the page's own assets being fetched, and no request carrying your picture.

Turn JPG, PNG and WebP files into a PDF now. The Image to PDF tool decodes your images and assembles the PDF inside your browser — nothing is uploaded, and no account is needed.

Open Image to PDF

JPG, PNG or WebP: picking the right source format

Most disappointing conversions trace back to the source format. The three formats you will meet most often store pixels in different ways, and that changes both how the finished PDF looks and how large it is.

JPG (JPEG)

JPEG (files ending .jpg or .jpeg) is a lossy format built for photographs. It discards detail the eye is unlikely to miss, which is why a full-resolution phone photo can fit into two or three megabytes. For pictures of people, rooms, scenery and anything with smooth gradients, JPEG is the right format to start from and the right one to keep inside the PDF. Its weakness is sharp edges: save a screenshot of black text on a white background as a low-quality JPEG and every letter gains a halo of grey fuzz.

PNG

PNG is lossless and supports transparency, so it preserves every pixel exactly. Screenshots, charts, diagrams, signatures and documents full of fine text should stay PNG — the file is larger, but the text stays crisp. A PNG of a mostly flat-coloured interface often compresses surprisingly well, so the size penalty is smaller than people expect, and hard-edged graphics avoid the smearing JPEG introduces around letters.

WebP

WebP is the newer format Google introduced, and it can be either lossy or lossless. It usually produces smaller files than JPEG or PNG at comparable quality, and browsers decode it natively. The one detail worth knowing is that a PDF cannot embed WebP directly: the page doing the conversion must decode it first and then write the picture into the PDF as JPEG or PNG. A browser-based tool handles that automatically, so WebP simply works, but a second lossy encode is possible if the tool re-saves it as JPEG. That is fine for photos and better avoided for crisp text.

What about GIF, BMP, TIFF and HEIC?

GIF is limited to 256 colours and, inside a PDF, usually only its first frame matters — acceptable for a small logo, poor for a photograph. BMP and TIFF are uncompressed or lightly compressed and produce enormous files; convert them to PNG for graphics or JPEG for photos before you build the PDF. HEIC is a special case with its own section further down, because it is the default on modern iPhones.

If your images are a mix of formats, you do not have to normalise them by hand first: a good browser tool accepts JPG, PNG and WebP together and encodes each one into the PDF sensibly. The one format you may need to convert before you start is HEIC.

Photos versus screenshots: two different jobs

Two kinds of material end up in these PDFs, and they have almost opposite needs.

Photographs come from a camera at twelve megapixels and up, are full of fine grain and gradual shading, and usually carry an orientation flag in their metadata. They tolerate JPEG compression well and generally need to be shrunk before they go into a document.
Screenshots and scans are captured from a screen or a flatbed and are dominated by text and thin lines at a known pixel size. They suffer badly under JPEG compression and are usually already the size they need to be.

The practical consequence is that a good tool should not apply one blanket compression setting to everything. If you merge a phone photo of a receipt with a screenshot of a bank statement, the photo can be scaled down and compressed hard while the screenshot keeps its pixels. When a tool offers a single JPEG-quality slider, set it for the material that matters most: choose a high value when there is a lot of small text, a lower value when the pages are mostly photographs.

How much resolution do you actually need?

Resolution only has to be high enough for how the PDF will be used. For a document meant to be read on screen, 96 to 150 DPI is plenty. For something that will be printed, aim for roughly 200 to 300 DPI at the final page size. A full A4 page at 300 DPI is about 2480 by 3508 pixels, so a 4000-pixel-wide phone photo has resolution to spare — shrinking it saves space with no visible loss. Storing a twelve-megapixel photo at full size on an A4 page, by contrast, spends megabytes on detail no printer can reproduce.

Step by step: building a PDF from images in your browser

Open the Image to PDF tool. Everything runs in the tab, so there is nothing to install and no sign-up.
Add your images. Drag them onto the page or click to browse. A good tool takes several at once and lists them in the order they will appear.
Reorder them if needed. Drag the thumbnails until the pages follow the sequence a reader will expect — front page first, appendices last.
Choose the page size. Pick A4 for most of the world, US Letter for North America, or fit each page to its image if you want the pages to match their pictures exactly.
Set the orientation. Portrait suits screenshots and documents, landscape suits wide photos, and automatic lets the tool decide per image.
Decide the quality. If the images are photographs, a JPEG quality around 75 to 85 keeps them small without visible damage. If they are screenshots of text, keep the quality high.
Create the PDF. The browser decodes each image, encodes it and lays out the pages.
Download and check it. Open the PDF, scroll through, and confirm the order and readability before you send it anywhere.

At no point does an image leave your device. There is no upload progress bar because there is no upload; the only delay is your own processor working through the pictures.

Page size and orientation: the settings that shape the result

These two options, buried in most tools' advanced settings, are the difference between a PDF that prints correctly and one that looks like a ransom note.

A4 versus US Letter

A4 (210 by 297 millimetres) is the standard almost everywhere except North America, where US Letter (8.5 by 11 inches) dominates. The two are close but not identical, so a document laid out for one prints with slightly different margins on the other. If you are submitting to a specific office, match whatever they ask for. If you genuinely do not know, A4 is the safer international default.

Portrait, landscape or auto

Portrait pages are taller than they are wide and suit text, forms and phone screenshots. Landscape pages are wider and suit wide photographs, spreadsheets and slides. The trap is choosing automatic on a mixed set: if half your images are tall and half are wide, you can end up with a PDF whose pages flip orientation every other page, which is unpleasant to read and awkward to print. When the material is mixed, pick one orientation and let the odd image sit with margins, or split the job into two documents.

Margins and the printer's edge

Consumer printers cannot print to the very edge of the paper; a few millimetres all around are unreachable. If an image is placed flush to the page edge with no margin, that thin strip can be clipped — the top of a heading, the bottom of a receipt total. Adding a margin of about 5 to 10 millimetres keeps everything inside the printable area and gives the pages a calmer look at the same time.

One image per page, or several

For documents that will be read and filed, one image per page is usually right: each page is a self-contained scan or photo. For pictures that are meant to be seen together, fitting several to a page saves paper and gives a contact-sheet feel. Decide before you build, because rearranging pages inside a finished PDF is more work than choosing the layout up front.

How to keep the PDF from becoming too large

Images account for almost all of a PDF's size; the text and the page structure are negligible. That means the size of your finished file is decided almost entirely by how the pictures are handled.

A single twelve-megapixel phone photo, re-encoded at maximum JPEG quality, can weigh five megabytes or more. Thirty of them at full quality is a 150 MB PDF — too large to email and slow to open. The same thirty, scaled to what a printed page actually needs and saved at a sensible quality, land in the region of five to fifteen megabytes.

Lower the JPEG quality. 75 to 85 is the sweet spot for photographs: a large reduction in size for a barely perceptible change. Below about 60 you start to see blocking in skies and skin.
Scale to the size you need. There is no reason to store 4000-pixel-wide images for pages that will be viewed at 150 DPI. Matching the pixel dimensions to the target DPI removes megabytes without touching quality.
Keep screenshots as PNG, but check the colours. A screenshot of black text on white compresses very well in PNG. A screenshot full of photographic gradients may be better as JPEG.
Go grayscale for text-only scans. Scanned documents and faxes are usually black on white; dropping the colour channels can halve their size with no cost to readability.
Do not embed the same image twice. Build the PDF once from your originals rather than layering a converted copy on top of the original.
Strip the metadata. Cameras write GPS coordinates, timestamps and serial numbers into photos. Removing that data saves a small amount of space and a large amount of privacy.

If a PDF is already too big, a compressor can re-encode the images inside it without you rebuilding the document — that is exactly what our Compress PDF tool does, again entirely on your device.

Finished the PDF but it is still heavy? Run it through Compress PDF to re-encode the images in place, or combine it with other documents using Merge PDF — both work locally.

Shrink the PDF

HEIC photos from an iPhone: convert the format first

If you have ever tried to convert iPhone photos and found that a website refused them or silently did something odd, HEIC is almost certainly the reason. Since iOS 11, iPhones have saved photos in HEIC (High Efficiency Image Container), also called HEIF. It is an efficient format that roughly halves file size compared with JPEG at similar quality, and it is excellent on Apple devices and largely invisible everywhere else.

The trouble is compatibility. HEIC is not universally understood: some Android phones, many older programs and most simple conversion scripts cannot open it. More importantly, a PDF cannot embed HEIC directly — the image has to be decoded and re-encoded first. A browser tool that only accepts JPG, PNG and WebP will skip or reject your HEIC files rather than guess at them.

There are three clean ways to deal with it:

Change the camera setting. On the iPhone, open Settings, go to Camera, then Formats, and choose Most Compatible. New photos are saved as JPEG and work everywhere.
Share as JPEG. When sending a photo, choose a method that converts it — for instance the export option that specifies JPEG rather than the original format.
Convert once before you start. On a Mac, Preview can export a HEIC photo as JPEG; on Windows, the Microsoft HEIF extensions let the Photos app do the same. Convert to JPEG, then add the JPEG files to the PDF.

One caution: many online converters accept HEIC by converting it on their servers, which is precisely the upload you were trying to avoid for a photo of an ID card. Converting locally — or changing the camera format on the phone — keeps that file on your device the whole way through.

Rule of thumb: photographs as JPEG, text and graphics as PNG, WebP when file size matters and quality is good, and HEIC never directly — turn it into JPEG first, on your own device.

Frequently asked questions

Are my images uploaded to a server?

No. The conversion runs in your browser using JavaScript. Your images are decoded, encoded and assembled into a PDF on your own device, and no copy is sent anywhere. You can confirm it by watching your browser's Network panel while you convert — no request carries your pictures.

Which image formats can I convert?

JPG, PNG and WebP are supported directly, and you can mix them in one document. GIF, BMP and TIFF are best converted to PNG or JPEG first. HEIC photos from an iPhone need converting to JPEG before you start — see the HEIC section above.

Will the text in my screenshots stay sharp?

Yes, if you keep the quality high and avoid heavy compression on text-heavy images. Screenshots are best kept as PNG inside the PDF; it is a low JPEG quality setting that makes letters look fuzzy.

Can I put several images on one page?

Yes. You can place one image per page for scans and documents, or fit several to a page for photo sets. Choose the layout before you build, since changing it later means rebuilding the file.

Is there a limit on how many images I can use?

Practically, the limit is your device's memory. A few dozen high-resolution photos are comfortable on a modern computer or phone; several hundred very large images may be slow, because your own processor is doing all the work rather than a server.

Does converting change my images or their quality?

The tool decodes each image and writes it into the PDF. If you lower the JPEG quality, the pictures are re-compressed and lose a little detail — that is the trade-off for a smaller file. At high quality the change is imperceptible.