How do you scale an image up/down?

I've been attempting to make GCN, Wii, 3DS and Wii U tracks, but the only images I'm finding are way too small.

I recently posted Wii Moonview Highway, and it would be way better with the image scaled up. How do I do this?

Well, you could scale up the image itself but idk how to do that. In game tho, you can increase the pixel count in a complete mode track by going to Options - Image - Resize. Then just change the values for the pixel count. Note: THIS ONLY WORKS WITH FILES YOU DOWNLOADED OR DREW. It does not work with URLs.

My Wii Moonview Highway track was a URL, so that explains why I couldn't find it. But I don't have access to Paint or Photoshop. I do have access to Pixlr, but it won't let me create a circuit with my Pixlr image. So, how do you download an image? (Or am I just forgetting what that means and it's really obvious?)

Okay, so go to the image URL. Right click (or hold tap for mobile) and you should have an option to download image, save image as, etc.

Thank you so much! I have started creating tracks from Pixilart, then downloading them and scaling them up to 1000X100. This helped a lot!