Went to YouTube and just perused Inkscape videos... found ones that showed how to repeat object along path.   None of them work for me!!  It seems like there is missing info in the videos???

Here's the 1st one I tried to utilize:
https://www.youtube.com/watch?v=3jve45Z60iU

I open a design (have tried different formats: .jpg, .png. .svg, etc.),  then create a circle.  Select circle, then, Path, Object to Path...  Then select Path Effects, Pattern Along Path, select Repeated, Stretched (altho' others no work either)... Select my design, select "Copy", and then click the "Link to path on clipboard" icon on the Path Effects section.

Nuttin'.  I get nuttin'.  What am I missing?

I'm using Ubuntu 18.04, if that matters (shouldn't!!)
TIA -- DK

(There´s something wrong in first place with Nick´s pattern: status bar says it´s 154 nodes where just 30 are needed.)

But anyway. You need pattern object which must be a vector shape - raster images won´t work and the circle needs to be converted to path as well.

I put a working example together for you to "decompile" the set up:

And here´s the link to the handbook about this effect:

http://tavmjong.free.fr/INKSCAPE/MANUAL/html/Paths-LivePathEffects-PatternAlongPath.html

Thank you...  once I converted the raster image to vector, it works just fine!!  THAT was the step I was missing!!!  DK

Don't know why, but getting double postings, and I can't delete the 2nd one... "Permission denied".