I'd like to jump in on this conversation as it's EXACTLY the problem I'm having myself. I certainly don't want to hijack this thread, but I feel I have the same issue going on.
Here is a blog that I set up almost one year ago:
It's a collaborative blog of 20 wedding photographers. We have allocated 4 photographers to post each day with a short paragraph of text. As you can imagine, we have over 900 photos at this time.
Each photo is sized to 900 x 600 pixels and we use Next Gen to create a database for each shooter and it dynamically sizes the photos on the index page. If the viewer clicks the photos, it's pulled up to full size.
We've had HUGE server problems this year with the traffic we're getting and I've called them a number of times. We use WestHost and I've used them on a number of other projects, including a very robust shopping cart for my business. I've had their servers tested and have determined they are one of the best for SQL database intensive sites. Our original server through GoDaddy was horrible and we thought it was a database issue.
It's been almost a year now of looking at server logs, having them analyze our site and constant testing. We have now determined that the major culprit in our sites slowness is the NextGen plugin.
We have the blog set up to display 20 posts at any given time. This is so each photographer has their work up for one full week before being kicked back into the archives.
From what we can determine, NextGen is loading the full sized images FIRST and they dynamically resizing or creating the smaller photos that are displayed on the blog. This is killing our site.
If you have any suggestions on how to resolve this issue, I'd really, really appreciate your help. As you can imagine, disabling the plugin and having to figure out some other Lightbox solution and going in and fixing a years worth of posts is quite a daunting task to face.
Thanks in advance!