Follow this simple steps:
Most of problems are related to file permissions or file access. If you are a new YaPiG's user, I recommend to use default values at first (not modifying config.php, just commenting $STOP line as said above), and then customize YaPiG. Once you have finished your probes, do not forget to change $USER and $PASSWORD
YaPiG requires the version 2 of the GD library to work. This library is a extension with some functions for handling images (creation, load, modify...). It is included in the standard PHP suite but many web hosting providers disable it. YaPiG will try to load it automatically if available.
Possible problems related with this are:
If you are the server admin, loading the GD library automatically when you start your web server is very easy. Search your php.ini file. Then open it and search for this line:
;extension=gd.so <-- Linux/Unix/Mac Systems ;extension=php_gd2.dll <-- Windows Systems
Then remove the ";" character and restart your web server. If this line does not exist add it.
For more information about this directive read the PHP manual
In some rare cases extensions might not be good configured by default. If this happends you might get this error running YaPiG:
Unknown(): unable to load dynamic library './php_gd2.dll' - The specified module could not be found.
If this occurs, search the file php_gd2.dll (on Unix/Mac the file is called gd.so) and then on your php.ini change this directive to the correct value:
; Directory in which the loadable extensions (modules) reside. extension_dir = ./extensions/ ; This path is relative to php.exe on windows systems.
If you have any other problem during installation of using YaPiG, please read FAQ documentation. If your problem is not contempled there go to YaPiG's forums. Before posting check if any other user had the same problem, and please include your operating system and yapig version. Thank you.
During YaPig installation it is created a file called global-gen.php on YaPiG's root directory. For reinstalling, just delete this file. Obviously, if you do this you will need to create all galleries you have again.
Upgrading from a version to other it is not automatically done, so you have to do it manually and some versions are incompatible with others. All 0.8x are compatible. A simple way to upgrade yapig is replace all source files included in the yapig package except config.php. In these versions the template has not been modified (only for repairing little minor bugs) so if you modified them don't worry, you won't lost this work, because is not neccessary to replace these files.