Hello,
In the listings of Groups and Pages, why do not you use _thumbnail.jpg images instead of _large.jpg ?
The thumbnails displayed in the listings are very small, so there is no need for an image with very high resolution.
And especially the size is significantly superior with _large.jpg images, which naturally slowed down strongly the loading of the pages.
For example, for one of the images in your EasySocial demo :
121 KO for _thumbnail.jpg
1100 KO for _large.jpg
Thank you
Philippe