and how much time would it take it from the time the picture is taken to its transfer to the SDcardClick your link. Read how many bytes per picture. Divide by 512 to determine the number of writes to the SD card.
Measure how long a write takes. flush() forces the dump of the buffer to the card, even if the buffer isn't full. A nearly full or nearly empty buffer makes almost no difference
A little multiplication and division, and you can determine the answer yourself.
and then uploaded to twitter through the wifi shield.You'll need to measure that yourself. There is no hard and fast answer. It depends on your network. But, it will not be fast.
I think this can be doneSo do a lot of other people. The number that can actually make it happen is a small fraction of those that think it is possible.