Far as I can see, the Organizer panel in IA Writer serves as a simple document manager for non-text documents as well as IA Writer documents. Double-click on, say, a Word document in Organizer i opens up in Word. That’s very useful for how I work.
Until now, I’ve been exporting documents from Ulysses when I’m done with them, in order to have an archive copy. IA Writer could save me that step, and that much alone could be worth paying for it.
I do like exporting out my Ulysses sheets for archive purposes. I prefer exporting in Word format as well as a Markdown text bundle. A text bundle is essentially a folder disguised as a package document holding the markdown text plus any associated assets such as images or PDF files that are embedded inside the Ulysses sheet. The Text Bundle helps to keep all of the text and attachments together in one package.
As @bowline notes, you can include an image using Markdown. You can also use iA Writer’s Content Blocks feature to include an image (though to use an image as a content block it must be in the same folder as your note or in a subfolder).
Either way, the image will only show up when you preview your document. It doesn’t show up in-line while you edit the way it would in Bear or Apple Notes.
You could throw Notebooks into that mix too.
It embeds images (copies them into its folders), but does not show a preview while editing.
To put a little spin on it, the images are hidden while editing to reduce distraction
I do not know of a way of changing the size of an image added to IA Writer either via content block or Markdown. I know that Ulysses let you set the size of the image directly. This is very handy for publishing