I don't understand what you mean by "gag" and "positive image". The GPL is a very good license, because it has one benefit that almost all other licenses don't

I don't understand what you mean by "gag" and "positive image". The GPL is a very good license, because it has one benefit that almost all other licenses don't: it restricts use of your code to free software. If you care about software freedom, or want to live in a world where proprietary software is a thing of the past, then that should be reason enough to use it. Positive image is not a clause in the GPL, so I really don't know what you mean.