Yes, participants (or their parents) can upload an image to replace their icons.
Here's what it looks like on the participant page:
Here’s what it looks like on the bottom of the main campaign page (unless participants are hidden):
Here’s where campaign admins can change the image:
Here’s how it works:
When participants receive their invite emails, there will be a special link for them to upload an image. No account creation or passwords are necessary.
Here’s what it looks like: