Custom volume icon: does the application's icon take precedence over a different set icon?

I like very much DropDMG, great work and very simple to use. Coming to my question, I am trying to use a custom icon instead of the icns icon that is in my app because it doesn’t look very smart as a badge of the DMG, but it seems that DropDMG gives precedence to the icns file inside my app instead of choosing the selected icon. Moreover, I have noticed that the hidden folder is correctly created with the right icon that I’d like to badge on the DMG. Am I doing something wrong or is this the supposed behaviour of DropDMG?

DropDMG gives precedence to an icon file that’s already in the source folder, so you just need to save the icon that you want to use there. The exact steps are shown in the documentation under “Manual.”

Thank you very much for your reply. I have done exactly as written in the manual (before coming to the forum for your help;) and I had the hidden folder with my chosen icon inside, but still, the icon of my app was used as the icon in the top bar of the DMG and in Finder–>Go–>Computer.
It is not a major problem, indeed, just to know if I have missed something. Anyway, thank you again for your help and availability

There’s not supposed to be a hidden folder. You should pick the top level of your source folder (the folder that you drag onto DropDMG) as the destination for the (hidden) .VolumeIcon.icns file.