1: you add spoilers tags by first using ( and typing spoiler in the middle of it like this, (spoiler) and then type anything you want in the middle. At the end you do the same thing but add / after ( So it should look like this, (/spoiler). So in short (spoiler) something here (/spoiler)
2: Just copy and paste pictures you want onto the signature. You can do this by going to the edit my profile section and you should find it. Or use imageshack
3:.... Meh
I hope this was helpful.