Showing figures from a paper in presentation
In my field, mathematical physics, I've seen many presentations with figures from papers, and it's perfectly acceptable to do so providing you reference the work either at the end on a separate slide or as a footnote.

If the figure does not consist of data collected by the authors, but rather, for example, the graph of a function, then you could of course plot it yourself and include your own figure. There would be no need for citation.