Whenever I am trying to take a screenshot with flameshot (by the command flameshot gui, I get this prompt saying “Share this screenshot with the requesting application”. Once I click share, then flameshot is turned on. Why is the prompt there? Is there a way to remove it?
Did you click on that Options… button? What’s behind it?
And did you save the screeshot to your local drive first? If yes, your system may be unaware of the corresponding mime-types. In that case you have to tell Gnome which app to use for handling .png / .jpg / … file-types.