on glitter graphics or photo bucket {or most graphics pages}
you select the picture by clicking it

then on the page that opens - down below the image it will say "copy this for forums" etc.

you can right click or double click to select & highlight all the words in the box
and then right click again and use copy

then you come back to your post or your siggy box and right click again to use the paste and that should put all the text into the box for you.

then all you do is preview it to see if it worked.

If there is a certain part you have trouble at let us know.