Image Duplicator
Generate multiple copies of an image and download them individually or as a ZIP. Files never leave your browser.
Drop an image or click to browse
Any image format — processed entirely in your browser, nothing is uploaded
Duplicate an image into multiple files
This tool creates exact byte-for-byte copies of an uploaded image — useful for bulk-testing upload forms, generating placeholder assets, seeding a design mockup with repeated thumbnails, or preparing identical files with sequential names for a batch process. Everything runs locally in your browser using the File and Blob APIs; nothing is uploaded anywhere. Set how many copies you need and a filename prefix, then download each copy individually or grab them all at once as a ZIP archive. For resizing or converting the copies afterward, try the Image Resizer or Image Compressor.
Built and maintained by Meet Shah · Last updated
What this tool is used for
- Producing many copies of a placeholder asset for a layout test.
- Generating a set of identically named variants for a bulk upload test.
- Creating repeated files to exercise a deduplication or an import routine.
- Producing a batch to test an uploader's concurrency handling.
- Making numbered copies of an asset for a template.
Frequently Asked Questions
- What does duplicating an image accomplish?
- It produces multiple copies in one canvas — a grid or a strip — which is what you want for a contact sheet, a repeated sticker layout, or a pattern tile test. Everything is composited locally, so the source never leaves the machine.
- Is each copy identical?
- Pixel for pixel, yes, because they are drawn from the same decoded source rather than re-encoded per copy. The only quality loss is the single re-encode of the final canvas, and choosing PNG avoids even that.
- Why does the output file grow faster than expected?
- Because compression works on the whole image, not per tile. A PNG of nine copies is not nine times a single PNG — the repeated data compresses well — but a JPEG re-encodes the whole canvas and the block structure does not deduplicate the repetition at all.
- What is the size limit?
- The browser's canvas cap, commonly around 16,384 pixels per side and lower on iOS. A grid of large photos hits it quickly, and the failure mode is a blank output rather than an error, so scale the source down before multiplying it.
- Should I use this to make a CSS repeating background?
- No — `background-repeat` tiles a single image at render time, which is smaller to download and sharper at any zoom. Duplicating into one file is for cases where the output has to be a single flat image, such as print or a platform that will not tile.
Common errors and gotchas
- Expecting the copies to differ. They are byte-identical, so anything keyed on content hash treats them as one.
- Generating a large batch of a large image, which can exhaust browser memory.
- Assuming filenames are meaningful to a system that deduplicates on content.
- Using identical copies to test a pipeline that is supposed to detect duplicates, which passes trivially.
- Downloading a ZIP and expecting it to be smaller, when identical files compress well but the source already may not.