When downloading a new ResinOS image preconfigured for your application, you have the “advanced” option to “Download configuration file only”.
I guess this option allow you to reuse a downloaded image for an other application without downloading again the full 1.8 Go (I know it’s compressed during download, but still).
Is there a doc somewhere on how to use this configuration file on an existing image ? Do you have to edit it (name and/or content) ? What would be the software to mount and edit the .img file without flashing it on a microSD card ?