I have been trying to apply a texture (a file in my case) to my planet Earth in my solar system in Hypershade.

I've created a new material for my planet and with that material selected, I open the Attribute Editor and then to the left of 'Color' I click the 'checkered' box (texture box I think), I then selected the file that I want to use and it's applied. The trouble is that it hasn't came out the way I wanted so for now I want to revert back to selecting a simple color but I haven't been able to ever since I chose a picture instead of a color.

I have attached a picture because I'm sure I am not explaining myself, in short, in the area I've highlighted in red, how do I 'bring back' the option to simply select a color.

And while I'm here, I have also attached the image that I'm trying to wrap-around my planet Earth. It's a small version, but I just wanted to know once you have an image like that, how do you know what the dimensions of an image need to be. . .in my case to fit nicely around my planet. You'll notice in the first image it seems that all you can see are the north and south poles.

Again, please pardon my ignorance.