Q. Can I reuse photos taken by a professional photographer as often as I like?

Copyright is held by the professional photographer. Permission should always be sought from the copyright holder when using images or photographs. This also applies to images purchased from commercial companies.

Reusing the photo/s depends on the agreement you have with the photographer. That is, did they sell you photos with an agreement / conditions that include rights to use / reuse them as you like?

The Australian Copyright Council (ACC) advises that copyright is held by the photographer, unless otherwise specified in agreement with them at time of purchase.

See the ACC information sheet Photographs: Copying Photos You've Paid For. Link below.

And ACC information sheet Photographers & Copyright. Link below.