Summarize the following:
These snap over the brick without the use of nails. However, the brick and clamp must be a very similar height to make a good fit. This may not work well if the recess above the brick leaves less than 1/8 inch (3.18 mm) depth of the brick's upper surface exposed, or if it forms a curved surface due to a concave masonry joint. As long as the masonry is not too old and soft, you can replace nails with screws for more secure anchoring:  Choose screws at least twice as long as the thickness of the lumber you are attaching. Select a masonry drill bit with a diameter equal to the screw's shaft's, not including the threads. Drill through the lumber and into the masonry. Insert and tighten the screw until firm. Avoid over-tightening. There are many epoxies, mastics, and contact cements that can bond to brick. Check the manufacturer's instructions before buying to find a product that works with the material you plan to attach, and that can withstand the expected temperature, weight, and weather exposure. This approach may work well for light loads on soft brick surfaces, which are difficult to drill or nail without crumbling. This tool drives hardened steel pins into the masonry using a gunpowder charge. It is rarely used for home projects, since lack of training or the wrong model could lead to shattered brick or injury. If you have some construction experience and have a large project to complete, this could save you a lot of time. Do not use a powder-actuated tool on hollow brick.

Summary:
Hang pictures from hole-free brick clamps. Install masonry screws. Use an adhesive substance. Complete professional jobs with a powder-actuated tool.