It's easy for us as small businesses like mine! We can upload our own photos or use existing ones from other sources without having too many restrictions in place that prevent it (like most platforms do).
There are also some pretty good templates available if you want something more specific than just an image/text ad but maybe not quite what your looking at doing online either - I'd have liked this better had there been even fewer limitations here though so could create my ads exactly how i wanted them rather then being limited by template choices / design requirements etc., they really need another section where users who wish to post images only may be able see all options before uploading one themselves otherwise its very difficult working out which is best option given such few possibilities!!