Always prefer hosting the content on SO.

Thus, prefer having your pictures on SE's imgu-account, thus ensuring they will stay available as long as the SE network exists, instead of using any other option which can get unavailable independently.

The same logic applies to stack snippets and jsfiddle or the like, with some extra-advantage:
Stack snippets are versioned together with the rest of your post, not separately.

If you want to also make the same example available as a jsfiddle or the like, feel free, some people prefer that. Though keeping both synchronized, respectively making sure they are actually the same, is quite an added burden.

Always prefer hosting the content on SO.

Thus, prefer having your pictures on SE's imgur-account, thus ensuring they will stay available as long as the SE network exists, instead of using any other option which can get unavailable independently.

The same logic applies to stack snippets and jsfiddle or the like, with some extra-advantage:
Stack snippets are versioned together with the rest of your post, not separately.

If you want to also make the same example available as a jsfiddle or the like, feel free, some people prefer that. Though keeping both synchronized, respectively making sure they are actually the same, is quite an added burden.