I flagged your 5 uploads for deletion because they were poorly resized versions of the original images. You can find all the originals here:
http://milktank.sakura.ne.jp/gallery_old.html
The ones you uploaded are in the gallery_old.lzh file. Also, the artists' name is gunner-l, add that as a tag when you upload them again.
It also wouldn't hurt to check how other images are tagged here. To see how tagging works you either go here:
http://miezaru.donmai.us/help/tags
or just open up an image and click edit to see the tags in a textbox and how what is written there relates to what you see under Tags on the sidebar.