Hello Sam,
Sorry for the confusions earlier. What I really meant was if the media manager renders all the images in it's original state, it would eventually take ages for media manager to render. The reason being that the browser has to render all the original images (although the size of it being displayed is in very small dimensions).
As for the best way around this, ideally you need to upload those images via EasyBlog's media manager. Perhaps, what we could do is to create an "auto generating" script where if EasyBlog isn't able to detect those thumbnails, it'll try to re-create them but it's going to be tricky if you upload hundreds of large images as it will definitely time out re-generating those images