copyright / licence for images

for every image i upload, a database entry is created (in wp_postmeta)

in the table is an entry wich looks like this:
_wp_attachment_metadata
a:6:{s:5:”width”;s:3:”160″;s:6:”height”;s:3:”160″;s:14:”hwstring_small”;s:22:”height=’96’ width=’96′”;s:4:”file”;s:13:”banner180.png”;s:5:”sizes”;a:1:{s:9:”thumbnail”;a:3:{s:4:”file”;s:21:”banner180-150×150.png”;s:5:”width”;s:3:”150″;s:6:”height”;s:3:”150″;}}s:10:”image_meta”;a:10:{s:8:”aperture”;s:1:”0″;s:6:”credit”;s:0:””;s:6:”camera”;s:0:””;s:7:”caption”;s:0:””;s:17:”created_timestamp”;s:1:”0″;s:9:”copyright”;s:0:””;s:12:”focal_length”;s:1:”0″;s:3:”iso”;s:1:”0″;s:13:”shutter_speed”;s:1:”0″;s:5:”title”;s:0:””;}}

how do i edit this fiels? how do i add a copyright-information for my images? if i copy an image from wikipedia/commons oder flickr i need to add gfdl- oder cc-licence-information, ho do i do that?