[PeterEde (Peter)]

Just noticed you said you had IS on while tripod mounted. It's a no no

small copy from photography forum

Image Stabilization is a great feature and is in my opinion well worth paying the extra dollars for – especially if you shoot a lot of lower light shots.
Having said this there is one time when you should definitely switch IS off because it will do more harm than good to your photos – when you’re using a Tripod.
Image Stabilization (and vibration reduction) lenses look for vibrations in your camera in order to reduce it – however if they don’t find any (like when you are using a Tripod) they actually can cause it – and as a result actually cause camera shake.

There are times when IS should not be used.
When using your tripod (as above) as IS is for reducing the shakes at longer focal lengths.
When panning shots at slower speeds. Otherwise you will cause the gyro to topple. this makes the image jump or give a double image.

There is a general rule of thumb to use when using any lens. Keep your shutter speed at least as fast as your focal length is set too. ie if zoomed to 200mm then set shutter to 1/200 or faster. you may need to increase iso to compensate.
This helps reduce how noticeable handshake can be.

Also I found dropbox to be a very lousy storage location when I used it. For my online storage I use flickr.com. Maintains your images in the quality they were uploaded.