Using CS6 with OS 10.9.4 I'm dragging and dropping a screenshot with a resolution of 1135x1006 pixels into file with a size of 5760x3600. the image is a rendering of a planet created in a different program and I need to compare its size to another planet already in photoshop. This means I need to decrease its size quite a lit to get it to the correct proportion. When I do this the image winds up looking like a 100x100 thumbnail or something, its terrible. I'm a photoshop newbie and even though I have read other online discussions about similar issues I don't understand what they are talking about. Here is the large planet I'm comparing the small planet to.
And when I import the image of the smaller planet and resize it it looks like this:
I can't have this sort of thing going on especially if I want to export the file at any decent resolution such as 2880x1800 or 3840x2160.