Yup, that looks pretty bad!
Looking at our code, our guessing looks little off. If you don't mind a quick code change, please edit the /modules/mod_sclogin/helper.php file. Around line 250, you'll see the function "getJFBConnectAvatarSize". In that block of code is:
if($picWidth >= 200)
return "large";
Update that first line to 100:
if($picWidth >= 100)
return "large";
That will force the large image more appropriately.
We're releasing version 4.1.1 of JFBConnect today. This update will -not- be included, so if you make the change and then upgrade, you'll need to do it again. It will be in the next release though.
Sorry for the trouble, and thanks for the report,
Alex