MediaStorage: resizeImage methods

Signed-off-by: Daniele Ricci <daniele.athome@gmail.com>
New column: att_compress for compression ratio/size

Signed-off-by: Daniele Ricci <daniele.athome@gmail.com>
Let the upload service do the compression work (TODO)

Signed-off-by: Daniele Ricci <daniele.athome@gmail.com>