Turn Photos Into One PDF for an Upload (Android)

Put the photos in the right order and combine them into one PDF, one photo per page — then check the finished size against the cap the portal states. A photo-based PDF is a stack of images in a wrapper, so it inherits their size: if the PDF is too big, make the images smaller before you combine them.

On a phone, Convertlix for Android assembles the PDF on the handset: the photos are opened through Android's own file picker, combined by code running locally, and never leave the device — no upload, no server-side copy, nothing to retain. The honest scope: Android 8.0 or later, sign-in is required (there is no guest mode), the free tier takes up to 20 images per PDF at up to 25 MB per file and draws on a server-set monthly allowance of conversions shown in the app, and the finished PDF lands in the phone's Downloads folder.

You're not imagining it — six photos make a 25 MB PDF

The arithmetic is against you. A phone shoots 12 megapixels by default, and a 12 MP JPEG of a printed A4 page typically lands between 3 MB and 5 MB — more in poor light, because sensor noise compresses badly. Six of those is a 20–30 MB PDF, and per-upload caps of 5 MB or 10 MB are common on government forms and job portals.

Fixable: the resolution, the framing and the colour depth. Most of those megabytes are recording the table the paper was lying on, plus detail far finer than the text needs — the same problem described in Why Is My Scanned PDF So Large?.

Not fixable: a page photographed at an angle in a shadow will never read as cleanly as a scan of it, and resizing a blurry page just makes a smaller blurry page. You cannot argue the cap down either, so if a reviewer must read a reference number, retake the photo rather than compress harder.

Photos versus scans of the same page

Two reference numbers. A4 at 300 DPI is 2480 × 3508 pixels, about 8.7 megapixels — roughly what a flatbed scanner aims at for archival text. At 200 DPI it is 1654 × 2339 pixels, about 3.9 megapixels, and stays readable on screen and in print.

So a 12 MP photo carries two to three times the pixels an A4 page needs, plus the desk around it. A scan — flatbed, or a phone in scan mode — crops to the page edge, so every pixel you keep is page; corrects the perspective; and can drop to greyscale, discarding colour channels a printed page never used.

Treat those as typical, not exact. 1600 pixels on the long edge is roughly 137 DPI across A4 — a sensible default for typed pages, a bad idea for small print.

What to do before you combine

• Crop to the page. Often half the frame is furniture, and it is the biggest saving available.
• Straighten it, and fix the orientation. EXIF rotation flags are honoured inconsistently, so a page that looks upright in your gallery can land sideways in the PDF.
• Downscale, then combine. Aim at 1600–2000 px on the long edge for typed pages; resizing by target file size is the shortcut when you know the cap.
• Drop to greyscale where colour carries nothing. A printed letter loses nothing; a stamped or highlighted page can lose the thing being checked.
• Convert awkward formats first. If the photos are HEIC and something in the chain refuses them, HEIC to JPG on Android (Free, Offline) is the step to do first.
• Consider the metadata. Phone photos carry GPS coordinates in EXIF, and whether that survives into a PDF depends on the tool that writes it. If you are unsure, strip it first with Remove GPS and EXIF Data From Photos (Android).

How to turn photos into a single PDF on Android

1. If you still have the paper, scan it rather than photograph it. Cam to PDF scans pages with your camera, cropping to the page as it goes, which removes most of the size problem.
2. Crop and straighten every shot. Image Cropper crops and straightens any image. The frame should end where the paper ends.
3. Resize before you combine, not after. Image Resizer resizes by pixels, percentage or file size; 1600–2000 px on the long edge suits typed pages, and ID pages should be left alone.
4. Name the files so the order is unambiguous. Pickers usually sort alphabetically, and IMG_20260902_1123.jpg says nothing about page order. Prefixing 01-, 02-, 03- is the cheapest fix.
5. Combine them into one PDF. Images to PDF turns photos into a single PDF, one image per page. On the free tier that is up to 20 images at 25 MB each, read through Android's picker and written back to Downloads.
6. Check the size against the cap, then read every page. If it is over, Compress PDF shrinks PDFs by re-encoding the images inside them; Compress a PDF Under 2 MB on Android (Free) and Get a PDF Under 10 MB for a Visa or Job Portal cover how far that goes.

When this doesn't work

The portal wants each document as its own PDF. "Upload your passport" and "upload one PDF containing all documents" are different instructions, and the wrong shape is a common rejection.

ID documents and certificates. Do not downscale a passport photo page, a national ID or a stamped certificate: colour, the hologram pattern and the machine-readable zone can be exactly what is checked. Keep those at full resolution and cut the size elsewhere.

More than 20 images on the free tier. Build two PDFs and join them afterwards, or move to Premium — batches up to 200 items and files up to 2 GB, at $9.99/month or $99.99/year, one active device at a time.

PDF/A requirements. Archives and some legal filings demand PDF/A, which is not produced here; use a tool that writes it and validate the file.

Portals that reject image-only PDFs. A PDF of photos has no text layer: nothing in it can be selected or searched. OCR & Text Suite pulls text out of photos and scans, but it outputs text — it does not write a searchable PDF. If selectable text is required, you need the original document or a tool that adds a text layer, which much desktop scanner software does.

FAQ

Why is my PDF of photos so large?

Because a PDF is a container around the images, not a compressed version of them: its size is roughly the sum of the photos inside. A 12 MP photo of a printed page is typically 3–5 MB, so six make a 20–30 MB PDF. Crop to the page, resize to about 1600 px on the long edge, and drop to greyscale where colour carries nothing — the same six pages can then come out under 3 MB.

What resolution do I need for a document photo?

For typed text, 200 DPI across the page is comfortable and 150 DPI is usually still readable; A4 at 200 DPI is 1654 × 2339 pixels, about 3.9 megapixels. That makes 1600–2000 pixels on the long edge a sensible target. Go higher — 300 DPI, or 2480 × 3508 for A4 — for small print, ID pages or anything a reviewer zooms into.

Can I reorder the pages?

Yes. The simplest route is to fix the order before you build the PDF, by renaming the photos 01-, 02-, 03- so the picker lists them in sequence. After the fact, page order is a list stored inside the PDF, so a page-manager tool can reorder, rotate or remove pages without re-encoding the images.

Is there a free way to do this without an app?

There are a few, with trade-offs. On many Android builds you can select photos in Google Photos, choose Print and pick "Save as PDF" — print-to-PDF is built into the system, but it adds page margins, scales each photo to the paper size and gives you no control over compression. Google Drive's scan feature is another good route that uploads to Drive by design, and a flatbed scanner beats a phone on image quality.

Does Convertlix upload my photos?

No. The photos are opened through Android's own file picker, combined into a PDF on the phone, and written back to Downloads; the app asks for no storage permission, and its single runtime permission is the camera, used only by the page-scanning tool. Its network calls carry identity, licence, quota, configuration and payment data and never an image — which is why the tools still work in airplane mode.

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Scan or crop the pages, resize them once, combine them in order, and check the PDF against the cap before you sit through the upload.