Download the .zip folder, extract the contents, and open the 12x18_Frame_Mockup.psd in Adobe Photoshop (CS6 or newer, including Creative Cloud).
A: Yes. You can upload the PSD to Photopea (a free online editor) or GIMP . The smart objects will be readable, though you may lose the specific 3D bevel effects if using older software. 12x18 photo frame psd free download exclusive