By using max-width/min-width or max-height/min-height css property you can show image in proper aspect ratio within the predefined height & width div box.
.imgClassNameMax
{
max-width : 161px;
max-height : 139px;
}
OR
.imgClassNameMin
{
min-width : 161px;
min-height : 139px;
}
Congrats ~ Found your blog on Google while searching for a related topic, your site came up, it looks good, keep them coming!