Check wherever all your RCT stuff is saved. They should all be in the same folder. That is, if you chose screenshot from the disk button in RCT. If you choose to press the print screen on your keyboard, you have to open an image editing editing program and paste it there.
You then have to change the format of the picture to a .gif file in an image editing program. Then you can post it here! Hope that helps!
Or you can e-mail me at firstname.lastname@example.org and I'll post a screenshot for you