Wow heaps of albums, we have similar image numbers but nowhere near that many albums.
We had an CPU issue as well and found it was related to our sitemap trying to be read by Google, which always timed out, so we had to turn it off until I made a few adjustments to it and broke it down to pages, news, albums and images. The images still does not work as it times out but I have a ticket on bugtracker that the devs are looking into to have the sitemap split into smaller chuncks.
Try removing the sitemap feature and see if that helps the load issue.
Cheers
GW