Free photo editing to change background

[Cunderthunt]

For a TV opportunity I need to have a passport-style photo, except smiling. I need to therefore make the background white and plain in one of my photos (there's nowhere I can do that in my house). Are there any free photo editing apps that can do this for me? I know you can get a free trial of Lightroom, but I'm scared I will forget to cancel it!

 

[SoulRebel]

Could you hang some white material/a sheet over a door for a plain backdrop? I did this when I updated my passport.

 

[newtoyou]

There are loads of free apps where you could cut around your head then add it to a white background. Pic collage is one of them. But it might end up looking a bit obvious. I think the advice above about using a white sheet is better.