It looks great as is. The curtains,...............not so much

You need to provide a clear picture of what you have without the curtains in the way. That is, if you want specific answers about casing the window.

Best I could do without taking off curtains

I would leave it - i think the curtains are charming :)

I would leave it. It's fine. If you wanted to case it, you would have to remove some of the wainscoting and cap. You wouldn't trim just above the wainscoting.

With the selection of traditional
Crown and wainscot I would have cased the window but that gets decided with the house as a whole. If none of your windows have casing leave it as is.

I agree. Leave as is.

With the better photos, adding jambs and casing isn't a simple add to. Would need to tear out the drywall returns, remove some wainscot & rail. Do-able, certainly but a bit complicated & beyond just tacking up more trim.

If you really want it cased, you need a trim carpenter. Probably won't have much luck getting one unless you have several other trim jobs that need doing. (If there is one working in the neighborhood, you can sometimes have better luck with small jobs because it is a close by job and they already have their tools in tow.)

Maybe a pic of the window without the curtain so we can see it.

Installing casing also requires an extension jamb. This definitely would of needed to be stipulated in your written contract and not just "implied or assumed". A written contract supercedes any " he said/ she said".

Casing also adds to the cost not only in material but labor as well.

Looks lovely to me! What room is that?

I totally see why you wanted it to look different. I don't love the look. However, as others have stated below, it seems the ship has sailed along with the contractor and would be a major undertaking at this point.

Saying the contractor is “long gone“ is very misleading since new casing and extension jambs were never part of the written contract. The contractor has absolutely no obligation to do any extra work.

To be fair, I love my contractor and I'm not upset with him. I just had another big learning about what I like and what needs to be communicated. I was wondering how difficult or how I would add trim/casing. Many have commented about the technical aspects of this which is very helpful and sounds too complicated to change at this point. Thanks for all the input!

Dee, what I can see of the room looks very pretty as is. Looks like a happy place to be!

@flopsycat1 thank you! My girls bathroom!