[Gimp-user] GIMP License/Copyright Question

[Eric Sarver <akorinza gmail com>]

I would like to know if files that I create with GIMP such as .JPEG, .PNG,
.GIF and the content within them, (such as characters I've drawn in my
case) will remain under my property or ownership and that I can distribute
these characters/images under a copyrighted license to prohibit others from
using my work, in other words when I distribute these images online or
somewhere, do the images remain my intellectual property? I am confused
because in the license it says that the license means that "The GPL is a
copyleft <https://en.m.wikipedia.org/wiki/Copyleft>license, which means
that derivative work <https://en.m.wikipedia.org/wiki/Derivative_work> can
only be distributed under the same license terms." Does this mean that
images or files created with GIMP must be distrubuted as open source files
under the GPL license for anyone to freely use for commercial purposes? I
am a very concerned artist and don't want anyone using my work.