I have written an Obsidian plugin that can publish notes from Obsidian as articles on DEV.to, which also deals with some Obsidian specific stuff, e.g. converting Obsidian medialinks to markdown links, separating title from content, and convert MathJax syntax to proper {% katex %} expressions; and it can handle subsequent updates, by storing the article id as metadata after the article is created.

But what the plugin really lacks right now is support for. The API documentation doesn't document any option for uploading images.

Is that possible?

Btw, the plugin can be found here. It's waiting approval before it's available in the community plugin list, but can be installed through BRAT.