Pre-upload file checker
Full instructions and common questions
Pre-upload file checker
Check file size, extensions, count and dimensions, then repair images in batches, recheck and package locally in your browser.
How to use
- Enter the destination’s actual requirements, choose files and review each finding.
- Confirm the output format and dimension strategy: preserve ratio, pad or center crop. Transparent JPEG conversion requires white-background confirmation.
- Run repair and inspect previews, actual bytes and dimensions. Retry failed items or resume unfinished items after cancellation.
- Download the ZIP and per-file report. Unmet outputs can also be downloaded and are clearly marked.
Try an example
Require PNG files up to 200 KB at 300 × 300 pixels. A wide image preserves its ratio by default and reports the mismatch. Explicit padding produces a 300 × 300 output; check its size again.
Limits and privacy
Check up to 200 files. Repair up to 50 JPG/PNG/WebP images: 30 MB each, 150 MB of originals in total and 40 million pixels. Handle animations separately. Exact dimensions are never reduced to meet file size; very small targets may remain unmet.
Common questions
Are files uploaded?
No. Checking, repair, previews and packaging happen in your browser. Originals are retained.
Does passing guarantee successful submission?
It meets the entered requirements; the destination may have additional rules. ZIP reports are review materials, not submission files.