HDR image converter (Ultra HDR JPEG)
Turn an ordinary photo into an Ultra HDR JPEG with a gain map, so highlights glow on HDR screens and it still looks normal everywhere else. Runs on your device.
Make an Ultra HDR JPEG
Runs on your deviceHow it works
An Ultra HDR JPEG is a normal JPEG with a second, small image tucked inside it: a gain map. Screens and apps that don't understand HDR show the normal photo. Ones that do read the gain map and brighten parts of the picture beyond ordinary white.
This tool saves your photo as the normal (SDR) image, then builds a gain map from its brightness: the brightest areas get the biggest boost, mid-tones and shadows stay as they are. The boost slider sets the most it can brighten, in stops (each stop doubles the light). The file follows the Google Ultra HDR v1 layout: the gain map is described with the Adobe hdrgm XMP fields, and an MPF index tells readers where the second image starts.
This is an effect, not a recovery of real light. A true HDR photo captures extra highlight detail from the camera; a converted one can only make existing bright areas glow.
Why it stays private
Your photo is decoded, analysed and re-saved inside this page. Nothing is uploaded, and the page makes no network requests while you use it. The new file doesn't copy the original's camera or location data.
Questions
Where will it look like HDR?
On an HDR-capable screen in software that reads Ultra HDR gain maps, such as recent Chrome and Android photo apps. Support in other apps and browsers is still growing and varies by version, so check on the device you care about.
Why does it look the same on my screen?
Your screen or browser may not show HDR. The file still contains the gain map; on other screens it can look brighter. Elsewhere it shows as an ordinary JPEG.
Will editing apps keep the HDR part?
Not always. Many editors and messaging apps re-save JPEGs and quietly drop the gain map. Share the original file if you want the effect kept.
Which boost should I choose?
Around 1.5 to 2 stops looks natural for most photos. Higher values make bright skies and lights glow more and can look artificial.
Want to keep the originals private? VaultWell keeps them encrypted on your phone. Meet VaultWell