An avatar is that small photo you see in every forum. Members can often choose one from the board-album. If you like a more personal appearance, you can upload a picture of your choice.
Get yourself in the
When choosing a picture, keep in mind all avatars are small in (file-)size. Often just 60x60 or 80x80 pixels.
Look in your forum for the specifications and resize your original to the right size and format. Make sure your reduced picture is still good looking!
Consider to add your (forum-)name to the picture to make your unique combination of picture and name. Now you're done and ready to present yourself !
Good luck !
Choose your image with great care, because it represents who you are, who you want to be or reveals something about your character. Be aware: You will attract people like yourself !