~snip~ ...I'm not sure how big these posts are alloweed to have a maximum.... ~snip~
Maybe the answer is below.
Images must be less than 1.5MB. Resize or compress your image.
Don't know whether it's now improved, also don't know whether this size for each image or all images in one post.
So far I haven't tried it, my ranking isn't possible. Only a few times saw other member's posts that failed to load their images.