My votes!

EU Flag: Pointless = delete.
Jazz Statue: Just change its pose and improve it a bit in colors and then keep, if not, delete.
Rock statues: Not pixelated version is good, keep and add a yellow/brown version.
Horizontal Waterfalls: They're a nice water surface (just make it a little less water-like and with better colors (aka redesigned) and then keep, if not, delete.
Inferno Trees: I don't really know if they fit, so no vote here.