Linking to Manually Inserted Images in Blogdown / Hugo

Manual Linking? Using blogdown for generating websites and blog-posts from Rmarkdown files with lots of inserted code and figures seems pretty awesome, but sometimes you want to include a figure manually, either because you want to generate something manually and convert it (say for going from SVG of lots of points to hi-res PNG), or because it is a figure from something else (like this figure from wikipedia). Where to?