dont worry, so am i!

im still confuzzed

Select "send to the Site"--> Fan art--> continue-->. At the
top of where the box that you send the picture is, click "My
gallery options." and then " Request to change my gallery
entrance picture." Pick one of the pictures you have
previously sent, and the mods will change it. It may take a
little while to work, and you can only do this every 3
months

After selecting Send to the Site --> Fan Art --> Continue,
there's a multiple bar of gallery options you can select
above the Send A Picture area. Click My Gallery Options, and
then 'Request to change my "Gallery Entrance Picture'".
Select a picture from the ones in your gallery to be your
entrance picture, and then after the mods have changed it,
tada! You have a new gallery entrance picture! You can do
this for Fan Images too, same process. Also, your entrance
picture can only be changed once every three months, so
choose wisely.