Currently it's not possible to resize your image within the Articles UI - you would need to resize the image externally and then re-upload the image into the Article.

It's really a major problem today and a bit ridiculous to have to resize the image itself to the exact size that it will have in the article and therefore to have to do several iterations to obtain a good result. Intercom must be one of the only solutions allowing html editing and not offering such functionality.

We'd like to request this feature be prioritized. It's pretty tablestakes for authoring an article of any kind, thanks!