When an image is called during a visitor's browsing, or multiple images, such as a slider, plus all the rest of the CSS, many PHP process are triggered. If the hosting is set to a standard 32Mb PHP memory allocation, that can easily fill, slowing the entire site down. Remember your Dashboard (admin) is part of your site just as much as the front page and your posts or pages.
Examine the size of the images you're using and don't rely upon WordPress or PageLines to scale them down to fit. In Features, don't use Aspect Ratio, but resize the images in a graphics editor to a standard size and use Static Height. Don't use gigantic images in posts or pages. Resize to fit in a graphics editor. IE doesn't even try to rescale images. It shows what it sees.
If you have just two images each of 3Mb in size, that's already 6Mb of your allocation because PHP has to scale them. If just five people browse your site, you're already at 30Mb, not counting the PHP code for the rest of the pages, slowing, and eventually crashing your site.
Ask BlueHost to increase the PHP allocation to 128Mb. Or, upgrade to a more feature-rich account. Meanwhile, control your images.