Vetrack,

You can recover the module with the rotator that you deleted off the home page already. If you hover over the "Admin" tab in the control panel bar at the top you can see "Recycle Bin" in the basic settings section. Once you get to the recycle bin, be sure to click the tab for modules and then you can reinstate the module. (You'll need to have administrative rights to the site in order to see the control panel & see the Admin tab)

You should be able to overwrite those images if you would like to use your own. You could also add your own new images, but you would need to modify a little code in the "HTML" view of the module along with uploading your images. And your images can be whatever size you want.

Yes, you are correct that you need to upload a zip file. Seems you have not uploaded a module to DotNetNuke before. The video library page (under "Resources" in the red navigation above) is your friend & there is a video on how to upload a module. 

Once you get the module uploaded you'll need to add it to a page.

Once you are able to upload a module & add it to a page you'll be ready to rock... also, there are also several rotators that you can find in the store

Hope this helps,

CBP