Ok, start with creating a new document sized 500×500 pixels and use the Paint Bucket Tool to fill canvas area with color of #355b00. After that create a new layer and apply the Elliptical Marquee Tool to make a sphere selection as on a picture below, then fill this selected area with color of #97f501 Remove selection with pressing Ctrl+D and for the image jitter apply Filter > Blur > Gaussian Blur