You do not know why she chose this photo. It might be because of the moment and the memory of the moment. And the text? She could thank him personally - I do not see a reason to communicate with someone who is close to me via Instagram. I would not say that Martin is/was not important to her or just some one who lifted her and nothing more.
Just to clarify, this is not about her telling him "thank you" personally or not (I completely believe she did thank him). They're now public people and they use their instagram acounts not only for personal, but also PR/marketing reasons. And if you're ending some collaboration (business, sport or personal, no matter) it is absolutely common to offically, publicly thank your partner. Even more so, if you're ending the partnership "on good terms". This is not for him but for her audience, gesture of respect and gratitude. Now there are many explanations why she didn't: they may didn't split on good terms after all or she simply forgot or she just need a quick PR lesson

but 4 years with Danielle Montalbano.
