As she has been tagged in this picture, Jess has a few options available to her to help diffuse the conflict. She can untag the photo so that only those people who are connected to Anna will be able to view the photo. She might also report the photo to Facebook moderators and hope that they will be able to help her get it taken down.
The outcomes Jess might expect are similar to those if she did nothing. Things may improve. The photo may be taken down or Anna may not realise it’s been untagged. However, Anna may still have the original picture and may simply repost it or send it on to others. Again, Jess doesn’t have the opportunity to discuss her concerns with Anna.