imbedded thumbnails (i think)

okay, forgive my neophyte language (it’s probably inaccurate) … i just started a wp blog, and this is the first time i’ve ever done anything with CSS or anything remotely like it. it’s fun learning, but i’ve hit a few snags. i’d like, for example, to insert thumbnail images into my blog in such a way that they link to the larger image, but without jumping to a different page (i.e., i’d rather have visitors click on the thumbnail and open a pop-up box of the image that can be closed without closing down the whole browser.) To link the thumbnail to the image at all, all I’ve done is insert the image as a link, which i’m guessing is part f the problem–but at the moment, it’s all I could come up with to give people access to the larger image without putting the whole whalloping pic into my post. I’m sure there’s a simple solution…any ideas? my next question is just as silly, and i’m sure just as easily solved: i’d like comments to be automatically approved instead of coming to my inbox every time one is posted. i haven’t been able to locate an easy “automatically approve comments” checkbox anywhere, though, so i’m either missing the obvious or need to edit a file to do this??? maybe??? appreciate your patience and kindness in helping me with these!