wp-photo-album-plus thumbnail issues

In wp-content/plugins/wp-photo-album-plus/theme/wppa-style.css on line 99 it reads:

.covertext-frame {
}

if you change it in:

.covertext-frame {
    text-align: center;
}

your problem is fixed. If you do not want to have to change this again after every update, read the instructions at the top of the file on how to make a copy first.

Alternatively you may also put the css in any other css file that will be loaded always.