Create a new Image when using resize()

This fixes a bug where cached images were being resized. The place
I noticed this was when turning on "scale_gfx" in cutscenes/credits.txt.
Since we use the Flare logo on both the title screen and the default
credits, the image was resized on the title screen after viewing the
credits.
Merge pull request #1082 from dorkster/renderdevice

Create a new Image when using resize()