I'm not familiar with NOSTr username setup that much , but based on the context you provided, to place a picture in your username, you'll need to check the platform's or community's settings and guidelines for customizing profiles.
Here are general steps that might help:
1. Log in to your account on NOSTr.
2. Go to your profile settings or options.
3. Look for an option called "Profile Picture" or "Avatar," or something similar.
4. Upload the image you want to use as your profile picture/avatar.
5. Save the changes.
If this doesn't work, you may need to check NOSTr's help center or contact their support team for more specific instructions on how to customize usernames with images. Remember to follow any guidelines and rules they have in place regarding profile pictures and usernames.