File too large or unsupported format? Diagnose an upload failure
A step-by-step checklist for file size, actual format, image dimensions, PDF restrictions, filenames and browser-side upload errors.
An upload failure does not always mean a broken file. The website may reject its size, format, dimensions, page count or filename. Start with the exact error message and the receiving site's published requirements.
Match the error to a useful check
| Symptom | Check first | Next action |
|---|---|---|
| File too large | Actual bytes, not rounded KB | Compress the image or PDF |
| Unsupported format | Real file type and extension | Convert to a supported format |
| Invalid photo dimensions | Width, height and aspect ratio | Resize or crop deliberately |
| PDF rejected | Encryption, page count, active content | Use an authorized clean copy |
| Upload completes but is rejected | Required pages, readability, naming rules | Inspect the final downloaded file |
Use file preflight or image inspection to compare the facts with the rules. A preflight result is evidence about selected technical checks, not a promise that an institution will accept the content.
Check the actual file, not just its name
Renaming picture.heic to picture.jpg leaves the original bytes in place. Use image conversion and keep the extension that matches the output. A file sent through a messaging app may also differ from the original because that app re-encoded it.
For byte limits, compare the exact number. AttachReady's 200 KB preset is 200,000 bytes; other software may show rounded values or KiB. For photos, pixels and DPI must be checked separately.
Rule out document-specific restrictions
A PDF may be encrypted even when a reader can open it. Some receiving services reject forms, embedded attachments, scripts or uncommon page sizes. AttachReady rejects encrypted PDFs and certain active-content features; it does not remove password protection or guarantee a malware-free file.
If a PDF is signed, preserve the original: compression, merging or page selection can invalidate a digital signature. Use a fresh document or the receiving organization's approved workflow.
When the file passes all visible requirements
Try the receiving site's supported browser, check the session has not expired, and review its filename restrictions. Remove unusual filename characters only when permitted. A network failure or server-side error requires help from the receiving site, not repeated destructive recompression.
For AttachReady errors, see troubleshooting and error codes. Contact support@attachready.com with the tool, time and requestId. Start with a synthetic example instead of emailing identity documents or credentials.