open the picture in paint. Find the button thats called Resize. Should be to the left in the menu(Atleast in W7 version). When clicked, a box will appear, choose pixels from the bulletpoint. Resize to around 1024px width, and u should be good to go.
But it is strange as you said in your other post that : On a visit in Guanaste province, north of Costa Rica, I took a picture of this beautiful insect ! If you took the picture yourself, there should not be any problem
I recommend reducing your images to around 800 pixels wide or less. That should do it, but dimensions is not the only consideration. Color depth also has something to do with it. If the image is saved as very high quality you could still exceed the file size limit even after reducing the dimensions. If this happens try re-saving it at lower quality.
Don't know about the copyright issue. That sounds like an anomaly.