The most common ad sizes (in pixels) are 125 x 125, 150 x 150, or 300 x 300 but there are lots of other options.
Osayizi abajwayelekile bezikhangiso (ngamaphikseli) angama-125 x 125 px, i-150 x 150 px, noma i-300 x 300 px kepha ziningi ezinye izindlela.