"Kill the chicken, and make the monkey watch"
Institute an editorial policy by which all convicted offenders are banned for life from the publication in question. Convince other publications to share such info, and act in the same way after definitive proof is presented. No second chances.
Publicize these events far and wide.
That will probably take care of 60-70% of the problem, at least the blatant cases such as the one above.
Unfortunately few publishers have the conviction to do that.
To answer your question: "Who do you ban among N coauthors?" To first approximation, all of them as co-authorship implies shared responsibility. However, that can be more accurately determined on a per-case basis as the result of detailed investigation.
Detecting instances fraud is trivial if crowdsourced. Blatant image manipulation as the one shown above would eventually have been noticed by a reader of that paper. Same applies to other similar kinds of fraud. Relying on a single overburdened editor and a couple of bored referees for that task makes it much more difficult. Hiring staff to essentially redo part of the research reported in manuscripts submitted to the journal is just laughable.
The point is to demand ethical standards as a publisher, and raise the stakes so high that the penalty of getting caught, guaranteed loss of professional reputation and possibly employment, offsets any gain from publishing a single or a series of papers.
Relying on automatic detection schemes is inherently unreliable. Smart people will always find creative ways to cheat more effectively. To illustrate my point, consider the unending arms race between virus writers and antivirus software companies.
To conclude, and since you seem to be quite green, I suggest you give this a thorough reading: https://en.wikipedia.org/wiki/Schon_scandal
It won't take many Schönen to drive the point home...