Hi Alex,
thank you i have also asked Stephane the author of prettyPhoto if its possible to change on his side to avoid this conflict and maybe theres even a better way around that i dont know of.. Btw this could be fine in connection with ngg: its beautiful, automatically rezises to window size if image is bigger and last not least its completly free. Have a look at this little demo by me (with unresolved confilct): https://sing.dudelidu.de/
best regards
bee