Twenty Ten: Removing Header Images I've Added, so they don't show up on random

Hi,

I am a new wordpress user, just created some pages for my job that I’m hoping to use as websites. The theme is Twenty Ten.

I was customizing the header with images that I uploaded – but the first few were grainy until I figured out the right size file.

I would like to use the random button to cycle through a series of images, but I can’t figure out how to delete the poor quality images I uploaded. Does this require CSS code editing? Is it difficult, or do I need to have wordpress installed on my computer? I’ve only used the online editing features so far.

Also, I was wondering if it was possible to create a header image in wordpress that would cycle through a series of several images while a person was looking at a single page – similar to what many universities and news sites use on their homepage, to emphasis a few key stories or images. I have no idea how to go about this, and would love to know if it’s even possible in wordpress.

Thanks so much!!