They are capable of delivering a bite, that by all accounts is rather unpleasant & can leave you unwell for couple of days. However, this is a very rare occurence, bites tend to be a last resort before being crushed, they are actually quite shy & docile, avoiding contact with humans if they can.
Females (like the one in your photo) tend to stay close to their web & hiding place. Males do wander, in search of a mate, they have much smaller abdomens. I remove these when I see them, females I'm happy to leave be so long as they are not in the bedroom, or bathroom. If they are outside, they don't concern me at all.