Why not just upload them to this site? Why bother with a third party? As he said, David Walsh is your friend. Also, if you are going to do construction updates, make sure the rides under construction don't look like they'd fall over. Finally, your pictures look very unfinished, and I'm not talking about them gamewise. Crop them. There is no need for half the screen to just be blank grass unless it is a shot of a clearing for upcoming construction etc. I understand the limitations for RCT3 when it comes to polys and it slowing down systems, but you should take the time to make your photos look like work was put into them, not just a screenshot and upload.
As far as the park goes, I like the hyper coaster and you did a good job custom supporting the inverted coaster. Been a while since I've seen a boomerang (or whatever B&M would call it, don't think they've ever actually made one) on an inverted coaster.