Metadata disappears. A regeneration drops it, a crop drops it, and marketplaces and messaging apps strip it routinely when they republish an image. The file that left your gallery carrying a machine-readable statement of how it was made can arrive at its destination carrying nothing at all.
There is now a free tool that puts one back: Mark an image as AI-generated. No account, no charge, no limit.
You supply a JPEG, say what it is, and download the same file with an IPTC origin declaration written into its metadata. That is the field platforms and marketplaces read when they want to know whether an image was generated by AI.
The declaration is yours, not ours. We do not examine your image to decide what it is, and the tool will not offer a guess for you to accept. It records the answer you give, and the screen that hands the file back says so. There are two answers on offer: the image was generated by a model, or a photograph was combined with AI-generated content.
Nothing is uploaded. The file is read and written on your own device. There is no address on that page that anything is sent to and no server takes part in the work, which is why there is nothing to store, delete or ask about afterwards.
Everything except the metadata stays as it was. The same pixels, the same quality, the same dimensions. Nothing is re-compressed.
The tool will sometimes tell you it wrote nothing, and each reason is worth knowing in advance:
- Your file is already signed. A cryptographic signature covers the file's current contents. Adding anything would change those contents, the signature would stop matching, and a public checker would then report that the file may have been altered. That is a worse position than the one you started in.
- Your file already says where it came from. There is nothing to add. You can read what it says on our marking checker.
- Your file already has a block of metadata. Photo editors and phones write one into ordinary photographs. Only one such block can be read reliably, so adding a second would make the file ambiguous rather than better marked. This is the common answer for a picture straight from a camera.
- The file is not a JPEG. Save it as one and try again.
Whatever the outcome, the tool points you at our marking checker, so you can confirm on a separate tool what your file actually says. That checker's own result for an unmarked file now offers the marker as a next step.
One thing worth stating plainly: a declaration in metadata is not a signature. It travels with the file and anyone can remove it, including the next platform that strips metadata on publication. It is the marking the rules ask for, not proof that nobody changed the file afterwards.