i-dont-bite-just-nibble asked: how do you apload the pictures?
If you have an SD card in your Wii, when you save screenshots from City Folk to the card, take it out and plug it into your PC (I use an SD card USB adapter, many laptops have readers built in) and copy them over to your PC. I add a watermark in Photoshop quickly before uploading.
Here are a couple of SD card adapters if you do not have one (I recommend the second one):