The amount of change allowed during the hires refinement pass.
Typical 0.65
The second pass generates from the enlarged first image. Lower strength usually retains more of that image; higher strength allows larger changes to texture, details, and composition.Compare the result with the first image if you need to preserve a face or other specific features. This setting is sent only while Hires fix is enabled.
The examples on this page were made from one prompt, one model and one seed, changing only the setting shown. Other pictures, models and settings respond differently; compare on your own request with the seed and the other settings fixed.