How to change avi/Sig with your own pic thats not from Es Wiki Gallery

[Sintan]

I have uploaded one pic to the wiki but idk what to do from there to be able to put it in my avi or Sig
1st pic I uploaded is Hinata.jpg

Other one that I wanna use for Sig I didnt upload yet cuz I figure I should know to do it first before moving on

Also the original size is too big to be used for avi or Sig

[Oreo]

Caeli made an excellent tutorial here. If you are still having problems I would be happy to help you through PMs.