Replace default --image flag with MarkFlagsOneRequired() from spf13/cobra

cmd/root.go

@@ -12,7 +12,7 @@ import (
 )
 
 const (
-	ReleaseVersion string = "3.1.0"
+	ReleaseVersion string = "3.2.0"
 )
 
 var (
@@ -119,6 +119,8 @@ func init() {
 
 	rootCmd.CompletionOptions.HiddenDefaultCmd = true
 
+	rootCmd.MarkFlagsOneRequired("audio", "code", "flash", "images", "text", "video")
+
 	rootCmd.SilenceErrors = true
 	rootCmd.SetHelpCommand(&cobra.Command{
 		Hidden: true,

cmd/web.go

@@ -483,9 +483,7 @@ func ServePage(args []string) error {
 		formats.Add(video.Format{})
 	}
 
-	// enable image support if no other flags are passed, to retain backwards compatibility
+	if Images || All {
-	// to be replaced with rootCmd.MarkFlagsOneRequired on next spf13/cobra update
-	if Images || All || len(formats) == 0 {
 		formats.Add(images.Format{DisableButtons: DisableButtons, Fun: Fun})
 	}