Can’t Control Featured Image Size

I am trying to manage the size of my Featured Images to 500-600 pixels across.

Sometimes, I upload a photo that larger than that, say 1,200px. Then I go into the Featured Image Editor and rescale the image to 5-or-600 hundred (I’m not sure I should be doing that, I’ve been advised to keep image files around 1,200px so Google will see them, but that’s just too damn big).

And, sometimes, I get the result I want – an image scaled down to 5-600 px

But sometimes, as in this case, I don’t, and the image actually scales UP to something much larger than I want.

What am I doing wrong here?

Thanks,

–PS

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