Why was my file rejected?

Match the symptom to the cause

It is too large

A very common rejection, and the easiest to fix, because most files are far bigger than they need to be. A phone photograph carries several times the pixels anyone will ever look at, and a scanned document carries a full-resolution photograph of every page.

Reduce the dimensions first with resize an image, then compress. For documents, compress a PDF. The full version, including how to tell whether the limit came from the page, the server or the application, is on file too large to upload.

It is the wrong format

The form was built to accept a short list of types and yours is not on it. On a photo this often means HEIC, the format Apple devices use by default, which arrived long after most upload forms were written. Convert it with HEIC to JPG, or a whole camera roll at once with batch HEIC to JPG.

Do not rename the extension. The receiving system reads what is inside the file, not what it is called. Full explanation, and a table of what to convert to, on file type not supported. If it is specifically a photo coming off an iPhone, photo won't upload from iPhone is the shorter route. If you are not even sure what kind of file you have, what is this file will tell you.

An email refused it

Mail has its own limits, and there are two of them: yours and the recipient's. The smaller one decides. Attachments are also encoded before they travel, which makes them roughly a third bigger than the file on your disk, so a 24 MB file can fail a 25 MB limit and look like a bug.

The published figures for Gmail, Outlook.com, Microsoft 365 and Slack, each linked to its source, are on email attachment too large.

The dimensions or the shape are wrong

Some uploads care about pixels rather than bytes. Profile photos, marketplace listings, ad creative, banner images and official identity photos all tend to specify a minimum size, a maximum size, or an exact aspect ratio. A file can be the right format and a sensible size and still be refused for being 1200 by 630 when the system wanted a square.

Two separate fixes, and people reach for the wrong one. If the picture is too big in pixels, resize it — that keeps the whole image and shrinks it. If the shape is wrong, crop it — that keeps the proportions correct and cuts away what does not fit. Squashing a photo into a shape it was not taken in is the one outcome nobody wants, which is why the crop tool cuts from the centre rather than stretching.

If a minimum size is the problem, there is no real fix. Enlarging a small photo invents pixels that were never captured, and any system strict enough to specify a minimum will usually notice. Find a larger original. There is a longer walkthrough of all three cases on image is the wrong size.

There are too many of them, or too many pages

Plenty of systems accept exactly one file, or cap the number of pages in a document, or cap the number of attachments on a message regardless of their total size.

Both directions are covered. To turn many things into one, use images to PDF for photos and scans, or merge PDF for documents you already have. To go the other way, when one document is over a page limit or a size limit, split a PDF into ranges and send them in sequence. If the rejected file is a PDF, PDF won't upload goes through page counts, passwords and scans in detail.

It is damaged, empty or locked

Test this before you try anything else: open the file on your own computer. If it will not open there, no website is going to manage it either, and no converter can rescue it.

• Truncated. An interrupted download or a cloud sync that stopped half way leaves a file that looks complete in the listing and is not. Download it again from the original source.
• Zero bytes. Common after a phone fills up mid-save. There is nothing in the file to recover.
• Password-protected. A locked PDF cannot be read by the receiving system, so it fails whatever check runs first. Remove the password in whatever created the document. No tool here will open a file you cannot open yourself.
• Saved as the wrong thing. The older .doc is a genuinely different format from a .docx. Re-save it, or export it as PDF.

It objects to what is inside the file

Less common, and worth knowing about because the error message rarely says so. Photographs carry hidden metadata: GPS coordinates, a timestamp, the camera's serial number, sometimes the owner's name. Some systems strip it, and some keep it, so anyone who later gets the file can read it.

Remove EXIF data shows you exactly what a photo is carrying before you hand it over, then strips it. Worth doing on anything photographed at home, whether or not a form ever complains.

Nothing was wrong with the file

Sometimes the upload failed for reasons that have nothing to do with your file at all: a flaky connection that truncated a large transfer, a browser extension interfering with the form, a session that expired while you were choosing the file, or a service having a bad day.

The tell is inconsistency — it works on a second attempt, or from a different network, or with a small file but not a large one. A smaller file is more robust against all of these, which is one more reason to shrink before you upload rather than after three failures.

None of these fixes needs an upload

Every tool linked from this page runs inside your browser tab, on your own processor. That is not a marketing line, it is a verifiable property: open your browser's Network tab while you convert something and watch what leaves, or load the page, switch off your Wi-Fi and convert anyway. How that works, and how to test any site including this one, is its own page.

It matters most for exactly the files that get rejected: the passport scan for a visa application, the payslip for a mortgage, the signed contract, the medical letter. Those are the ones worth not handing to a server you know nothing about. If you would rather browse than diagnose, the full list of tools is one click away.

Frequently asked questions