Photos taken on recent iPhones and Android phones are HDR: their highlights are brighter than white on an HDR screen. Upload one to WordPress and that is usually lost. WordPress turns HEIC uploads into a standard JPEG, and the sizes it makes of a gain map JPEG keep the HDR only when you upload from Chrome or Edge.
This plugin sends the photo you uploaded to HDRJPG, which converts it into web-ready files that keep the HDR:
Wherever the photo appears in your posts and pages, in an Image block, in a gallery, as a featured image or inline, the plugin serves these files with the HDRJPG markup. Each visitor’s browser gets the version it shows in HDR. On a screen without HDR, visitors see a normal photo.
A conversion takes a minute or two. The photo keeps its normal version on your site until it is done.
Each photo converted counts as one conversion, whatever the number of sizes and formats. The free plan includes 300 conversions a month, and the photos carry an HDRJPG watermark. The paid plan has no watermark and no cap. See hdrjpg.com/pricing.
This plugin uses the HDRJPG API, a service run by Tin.cat, to convert photos. When you convert a photo, the original file you uploaded is sent to https://api.hdrjpg.com together with your API key, and the converted files are downloaded back into your uploads folder. Nothing is sent until you add an API key and convert a photo, or turn on automatic conversion. Visitors to your site load the converted files from your own server; they never contact HDRJPG.