Do not try to edit photos in SAI 2. It lacks advanced filters, layer styles (like drop shadows/bevels), and CMYK support. It is an RGB painting program only.
If you are looking to create webtoons, comics with speech bubbles, or graphic design work, SAI 2 will frustrate you. It has a very basic text tool and lacks sophisticated shape rulers or panel splitting tools. Most artists have to export their work to Photoshop or CSP just to add text. paint tool sai 2