You can place stands on the lower arms, right behind the knuckle (not on the ball joint), or if your stands are compatible with the pinch welds (won't crush them) areas circled below, and you have a standard floor jack with a saddle (not a small-contact-point, bottle jack) you can jack under the lower arms and put the stands in the OEM designated areas. I can't see your jack and stands to judge so that is your call, usually better to have the jack stands on the pinch weld area rather than the irregularly shaped lower control arms. There are adapters to go on the standard A-frame style jack stands to more evenly apply weight distribution on the pinch weld areas. IIRC, Amazon among others, sells them.
Personally, even if not under the vehicle, I would not rely on only the jack itself, not even with a wheel under the vehicle as a supposed-backup. Get jack stands and use them. Leave the jack in place also, if/when you can. If you can't leave the jack in place because of suspension work or whatever, then I'd at least move it to the subframe, just jacked till it makes contact but does not take significant weight off the jack stand(s).