I make it a policy to shoot 1/2 - 1 stop underexposed when shooting in bright sunlight. It usually makes the colors denser (when there is color with an all black NS paint scheme). Your photo is a little washed out, but it can be easily saved with a little processing. I took your photo and raised the overall desnsity, upped the contrast slightly, and popped the color a little bit by upping the saturation a touch.
Find a photo/image processing software package you like and learn how to use it. Many people use Photoshop, but I use Paint Shop Pro. Almost every digital image needs some processing before it can be uploaded (and accepted) at RP.
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