[Can you use Paint.net to make a header for a wordpress site?]

Hi,

I'm a newbee-and I'm trying to create a website on wordpress.com-

 

I have a photo of myself and was wondering if it's possible, to create a header -

 

using the photo-and editing it-

 

I'm new at this-and was wondering if using Paint.net could do it-(I hope there's some instructions

 

somewhere)or do I need something completely different-hopefully free?

 

 

Thank you

 

Jim