There is a size limit and limit to the number of images per post. I use an old MS Office Picture Manager and use "Predefined width by height" and then "Web Large (640x480)," but I think the limit may be 1.9MB. One can only post 10 images per post.
I don't have any suggestions for the shaft - maybe a fountain with a pump continuously going over. Or, I suppose you could find a cleaning tank and use gallons to submerge. Neither would work for me.
Janey - Neat people never make the exciting discoveries I do.