As far as the pictures, remember they are not located on our website, they are located on an image host. It is the fault of the image host when thumbnails do not load quickly.
Spoilers work by hiding the content. The content is still there, it's just not visible. I would have to dig into the modification to make certain, but I'm pretty sure the images would still be loaded, so it wouldn't save any time even if they are hidden.
What would be nice is a feature in the XenForo forum software has which shortens display of quotes, and shows a "read more" link to open it up to see the entire quote. It is often used to quote larger sections of a newspaper or blog site to show enough of the text for you to decide if you want to read the whole quote.
I've been looking at our forum's software site for spoiler modifications and I'll see if there is one like I just described too.
Be assured, we have many plans to extend the features of our forum. We began in August about 8 months ago to get enough good features to be worth opening to the public only recently, and we plan on always being on the lookout for good features to add.