Most image formats are already compressed. But in fact, if I take an image and compress it [gzipping it], and then I compare the compressed one to the uncompressed one, there is a difference in size, even though not such a dramatic difference.

The question is: is it worth gzipping images? the content size flushed down to the client's browser will be smaller, but there will be some client overhead when de-gzipping it.

Please advise.