grab: Use JPEG quality setting "95" instead of "100"

A setting of 100 is purely academic, it creates bigger files but pixels
hardly differ more than a single lsb compared to a 95 setting.
grab: Avoid evil os.system, run async, release resources

os.system uses too many resources, eConsoleApp is much safer.
This also makes the request run asynchronous.
Clean up the temporary file after completion.