I had to post this because after searching high and low I couldn't find a solution to my problem anywhere.
My gallery2 installation includes plugins like checkout, checkout paypal, remote, image block, colour packs, watermark, password protected albums, various image toolkits including imagemagic and GD.
The problem I was having was when deleting albums, and when trying to delete more than one image at a time. I also had the white screen problem or the progress bar would stop 3/4 of the way after processing a request to add a password to any particular album.
A lot of people put this down to memory limitations and recommended creating a php.ini file that manually addressed low memory issues. But this didn't work. The alternative solution was to create a local .htaccess file in the gallery2 local folder to address the same low memory issues. Still didn't work. Clear database cache, didn't work. Running optimisation tutorial didn't work delete user sessions, no acceleration and other settings didn't work.
After playing around with settings and finding no solutions for someone like me on shared hosting. I was satisfied that gallery2 was just finding it difficult to operate on my basic shared hosting plan.
Then I found the option in general settings for "locking system". File based or database based locking? I had a little read up about this setting and changed it from file based locking to database based locking. My gallery system now works a treat. I can delete whole albums without experiencing white screens. I can assign passwords to albums without experiencing timeouts or white screens.
I hope others may find this useful because it had me totally lost for solutions for quite a while. Was considering moving to coppermine. But now I know gallery2 is actually as good as others say it is.