Is it an unusual size? You don't think you could find one the correct size?

I should have mentioned that this painting is big - 20 x 28. I’ve been searching eBay for frames and see very few that are the right size. It’s very frustrating that so many sellers give only the outside measurements of the frame. The useful measurements, if given, are tucked away in the description.

I don't know if you are doing this, but you can shop for framed art on ebay or etsy and not just empty frames. There is some fairly cheap and grotesque art available that you could sacrifice for its frame.

Also check Goodwill art online.

And salvation Army Thrift store.
The geometry involved in cutting down an old frame can be complicated ( and I am math challenged)...you will look a long time to find a nice frame bigger than your picture and still be able to miter the corners.
And remember...paint does wonders for a frame...or something like a decortaing wax.

Thank you for the input. I like old paintings and should have followed my own rule - Don’t buy unframed pictures!

I have looked all over. I don’t think a nice one in this size is going to turn up. I’ve seen some larger ones on eBay, even ones that would need only two corners recut. I just wondered why there is no DIY help out there!

If it's on stretched canvas you can hang it without the frame and just keep looking until you find the right one.

No one? It seems like an obvious solution, but then I’m often swimming against the tide.

Talk to a custom picture/art framer.....they may have some ideas. Or if you find a bigger frame, can you mat it to fit your painting? A plain frame can be added to....like quarter round, rosettes, and other wood decorations to make it look antique...A picture/art framer could talk to you about this.

I’ve had an antique frame cut down to fit a vintage print and it worked fine. The frame didn’t have any embellishments on it, it was a deco era frame.

OTOT, if the frame is fancy, you’ll have to cut it oh so carefully so mitered corners look nice and well matched. Not easy to do. Not to mention that if the frame is plaster and wood, not solid wood, plaster might get damaged in the taking apart/putting together process.

Google "picture frames in custom sizes" and there are several. I wish I could remember the name of the one I used because prices were very reasonable. One site has a very good sale on.

Edited: My husband found the site I used; it's American Frame.com. I hope that helps.