I have a similar problem with some albums (400 or 700 images)... I use Safari 3 but I only have a powerbook G4, the edit page for the album takes around 5 minutes to load and safari displays an alert message like "you're running a too long script, do you want to continue ?"
I'm uploading images via FTP but in this case, images don't appear in albums
I've tried to use "Refresh the database" on the main admin page, it works once, I could add informations on images via PhpMyAdmin to save time
but one image was missing (no entry in the database), so I went to the album page thinking ZP needs to create cache image, it works but I had to wait for the loading of the page
I don't know if it's possible (and if it's the right place to make a suggestion) but I could be very nice to have a page on the admin like for example : "X latest uploaded images"
it could be a way to save time and don't have to use the edit album page for editing informations and pre-cache only new images ("pre-cache images" also is too long too with a "big album")
(sorry for my bad english)