So if you want to change your avatar, go to My Mibba, then on Profile section, click on avatar. And there, you can upload your avatar. To upload your photos, go to the same section and click on Photos. As for profile layout, still go to My Mibba -> Profile then click on Custom Profile. There, you can edit your HTML so that you can make custom layout to your profile. I'm not good with HTML so I just use default layout. ~(^_^)~
I hope this helps you a little. If you have any more questions about mibba, you can as me or just anyone else. People here are very friendly and helpful. You can also go to the Forums and find help there.