A couple of things to inspect. Remove the HDPI checkbox in the settings tab. Also if you uploaded an image or vector before - and it had 150px (let’s say you see that size was too small) - then delete it
If it still has the same filename it will revert to that original size. You need to delete or keep the file it doesn’t matter, but you do need to change the filename, especially if it’s uploaded back to back in the same session.
I’ve found simply adding another name, or character (home-headshot-1, home-headshot-2) something like this. It will recognize there’s been a size update.