STL,
Yes there will be two files saved on your camera's memory card. One will be a JPEG and the other RAW file will have an different file extension depending on your camera make. Mine creates .NEF for the Nikon RAW files.

Cool! Picasa supports RAW files! It didn't back when I used it.

Yea, if you are taking photos you intend to keep then shoot JPEG + RAW. This way if you have any problems adjusting RAW to your liking you have your JPEG to fall back on. If you are just experimenting then just use the RAW setting to try your hand at RAW processing.

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2010 Silver Ford Ranger XLT 2.3L 2WD StyleSide Reg Cab Auto, Open 7.5" - 4.10 diff.
TruxEdo tonneua cover, rubber bed mat, Ranger all weather floor mats.