The DMG has example images demonstrating how the cover rules and the optional flanking rule work on a grid. DMG p. 250 has the examples for a square grid at the bottom, and p. 251 has the examples for a hex grid at the bottom.

However, for some reason, the images on the DNDBeyond version of the DMG are broken - in that the arrows that point from one corner of the highlighted creature's space to the corners of an enemy space (or to the corner of the other highlighted creature's space, for flanking) are missing.

It should look like this:

...But instead it looks like this:

Please fix this bug. Both the square grid and hex grid images are bugged in this way.

...Any news on this bug? It's still not fixed, as can be seen here: https://www.dndbeyond.com/compendium/rules/dmg/running-the-game#OptionalRuleFlanking

Quote from DiceyDM >>

Hello, V2Blast! 

Thanks for bringing this to our attention. Both the square and the hex grid images now have arrows. 

Happy Gaming! 

 Thanks for (finally) addressing the issue. :)