I have Windows 11 scaling everything to 350% because that's the only way things are readable for me on a 4K monitor. So, I therefore have as Windows 11 settings for IMatch's executable: Compatibility>Change high DPI settings>High DPI scaling override:>Override high DPI scaling behavior. Scaling performed by system.
This causes IMatch to be scaled at 350%, which is okay. But, as 100% scaling would be too small, I think an optimum setting would be at, maybe, 225% or so.
Is there any way that I can have IMatch (or any other application, for that matter) be scaled on a per-app DPI-setting, apart from what is specified for system-wide use from within Windows itself?
IMatch is set to automatically scale to the system DPI. It is DPI-aware, in Windows speak.
See Configuring IMatch for High-DPI Screens and Easier Reading (https://www.photools.com/3242/configuring-imatch-high-rez-easier-reading/) for additional hints.