Gallery images aren't re-sized. You'll need to use CSS to re-size them at specific locations. This should be doable using the below CSS for example.
Code:
#mod_login_avatar,
.cbThumbPict {
max-width: 50px;
}
The above will limit the width to a maximum of 50 pixels for thumbnail images. It's often best to use max-width and/or max-height to avoid forced height/width as something smaller than 50px would be stretched in such a case, but will not be using max- usages. I suggest adding to the bottom of your Joomla template CSS file so it can apply to all locations of your site that the avatar may render through API.
krileon
