Hallo,
in the meantime I have my site up and running with zenphoto 1.4.5. Only one small issue remains: the captcha images (e.g. for commenting images) seem to be broken.
The zenpgoto error log does not show anything related. The GD library is enabled (freetype support on), watermarking works as well using a png watermark. Server Logfile shows that an image seems to be delivered with HTTP code 200). The image creation procedure seems to be running to the end (checked by adding an additional debugLog statement as last line in c.php). Background image is in place (path applied in c.php seems to be correct).
PHP version: 5.4.11 GD version: 2.0.34 compatible
Changing the theme or the web browser does not help either.
Any ideas what else could be wrong or how to further investigate?