Every converter here is free, full size, no account.Photos convert in your browser and never leave it. Video and e-books do need our server — those we delete right after.
By ShinobiTools Team · Last updated: August 2026
Converting an image is a two-second job, so the interesting question is not which tool is best — it is where your photo goes. Most free converters upload it to a server and count your conversions. A few never send it anywhere. Here are six, checked 6 August 2026. ConvertNinja is ours, and it is one of the ones that never uploads.
Convert an image, free →Checked on each tool's own page on 6 August 2026. The last column is the one most comparisons leave out.
| Tool | Free limit | Account? | Uploads your file? |
|---|---|---|---|
| ConvertNinja | None | No | No — runs in your browser |
| CloudConvert | 10 a day, 1 GB per file | Prompted | Yes |
| Convertio | 1 GB per file without an account | Prompted | Yes, kept 24 hours |
| iLoveIMG | Size and batch limits | Prompted | Yes |
| Squoosh | None | No | No — runs in your browser |
| Built-in (Preview / Photos) | None | No | No — on your machine |
It is not a marketing distinction. A converter that uploads has to receive your photo, store it somewhere while it works, and then delete it — and you are trusting a privacy policy that it does. A converter that runs in the browser does the work with code that is already on your machine: there is no upload to intercept, no server copy to leak, and no retention policy to read.
It also means it keeps working with the network off, and a batch of two hundred photos does not queue behind other people's jobs.
The trade-off is honest: browser conversion uses your own processor, so a very large batch on an old laptop is slower than a server would be, and the exotic formats a server-side tool supports are out of reach. For everyday image formats, that trade is worth making.
We opened each tool's own page on 6 August 2026 and noted the free limits, the account requirement and whether the file is uploaded. We did not benchmark output quality: for a straight format conversion the pixels are the pixels, and the only place quality varies is compression, where Squoosh's manual control is the honest recommendation.
ConvertNinja does its work with the browser's own image APIs, which is why it needs no server and why we can say plainly that nothing is uploaded — there is nowhere for it to go.
Looking for a specific conversion? HEIC to JPG, PNG to JPG and WebP to JPG each have their own page here, with the same no-upload conversion described above.
Scanning paper documents rather than converting existing image files? Our sister roundup, best free document scanner tools, compares six free options the same honest way.
No, it does not. The conversion runs in your browser with code already loaded on your machine. You can test it: turn off your network after the page has loaded and it still converts.
iPhones save in HEIC, which Windows did not support natively for years. Either install Microsoft's HEIF codec from the Microsoft Store, or convert the files to JPG first.
No. Drop the whole camera roll in. Because it runs on your own machine, the only ceiling is your computer's patience.
JPG for photos you are sending to someone or printing. PNG when you need a transparent background or a sharp screenshot. WebP for a website, where it is meaningfully smaller than JPG at the same quality.
Converting to JPG or WebP re-compresses, so a tiny amount, once. Converting the same file back and forth repeatedly does compound it. PNG is lossless, so it never does.
6 August 2026. Mail [email protected] if a limit here has changed.
Yes — the same free-vs-paywall trade-off shows up there. PicReviver's Palette.fm comparison checks watermarks and output size the same way this page checks converters.