Change the Declared DPI Resolution
Modify the DPI (dots per inch) value stored in the metadata of a PNG or JPEG, without touching a single pixel or recompressing the file content.
How it works
The DPI stored in an image file is only indicative metadata used by some layout software to calculate a default print size: it represents no pixel data. This tool locates the relevant metadata block directly (the pHYs chunk in a PNG, or the APP0/JFIF segment in a JPEG), replaces or inserts it with the new value, and leaves everything else in the file — especially the pixel data — strictly unchanged.
Does the quality or file size change?
No: no pixel data is decoded or re-encoded, only a small metadata block is added, replaced, or slightly shifted. The file size therefore changes by at most a few dozen bytes, with zero loss of visual quality.
Why do some applications still ignore the modified value?
Some applications rely on other metadata (such as the EXIF XResolution/YResolution tags embedded separately by cameras) rather than the pHYs chunk or JFIF segment modified here. In that case, the print size shown by that application may not change, even though the metadata targeted by this tool has indeed been updated.
100% local processing: metadata modification happens directly in your browser, byte by byte — your image is never sent to a server.