I believe I understand what you're saying, Dam. Rather than create a zip file with individual 3DAR images, put all of the 3DAR images in an xcf file. Then, you keep all the 3DAR's together in one neat little package, and since GIMP will already be open, just open up your 3DAR xcf file and drag/drop the desired one(s) into your work. Is that correct?
Sounds like a good suggestion to me.