picbuf =heather + logical screen + grafic control + image description + image data(these last 3 have the actual frame, only 1 frame) + trailer(3B)
i can do in these way?

Since it has only 1 frame then why do anything? You would just use the entire file so picbuf = buf. No need to pick out each section and then turn around and put them back together again.


the Global Color Table have 12 bytes?

I don't know how many bytes in table. It varies from one gif file to another