The title says it all really. They asked for one of each of the sizes, so here: (Erase the two 000's at the beginning and end)
for avatar:
[img]000http://i47.tinypic.com/27xozm0.jpg000[/img]
for thumbnail:
[img]000http://i50.tinypic.com/v7s7l1.jpg000[/img]
for regular:
[img]000http://www.chickensmoothie.com/oekaki/image/image.php?id=1395819&size=large&format=auto&rev=1360542863000[/img]
Enjoy!