We have noticed some issues between stated size and what actually works...
I've been using this site for years (no affiliations) they now have subscription options but when I used it last month my 2-3 pictures were all free with no problems. I use their set defaults. Remember to download the image (3 steps -- drag picture over, reduce image, and download) so you can upload it here.
https://www.reduceimages.com/
Try it and see if it works!