I had version 1.7.4 installed and just updated to version 1.7.7 using the steps outlined in \docs\Update.english.txt
All I had to do was copy my existing "config.php" to a temporary location, dump the contents of the .zip update file into the gallery directory on my site, and replace the new config.php file with the old one.
The site appears to be working just fine, but at the bottom, it still says Powered by 4images 1.7.4. What can I do to make this say Powered by 4images 1.7.7?