Simple and portable: developers should be able to implement PNG easily.Legally unencumbered: to the best knowledge of the PNG authors, no algorithms under legal challenge are used. (Some considerable effort has been spent to verify this.)
Well compressed: both indexed-color and truecolor images are compressed as effectively as in any other widely used lossless format, and in most cases more effectively.

I am not expert of these type of things but what I have heard that, Google hates over use of flash work on your web page and surprisingly Bing loves flash images.

Make me correct if I am wrong.

Really good post, couldn't have asked for more!!..

This is really a good one stuff in this. I really admire tot this. Plz serve some more about it. I ma waiting for your new update on it.