ellwangen

You may define the width and height of the iframe.

Without a link to the affected site it’s quite hard to figure out your mistake. I guess the path to the images is wrong.

There are sripts to avoid spam e.g.
https://www.ioerror.us/software/bad-behavior/

Sounds good that far. So the iframe itself works but the new site is not found? Is it in another folder?

Perhaps you forgot to close the tag.
<iframe src="index.php"></iframe>
I tested it without and it didn’t matter.

Which website is concerned? What exactly did you want to do with the meta refresh? Of course an iframe will disappear if the browser is overwriting the current site with the one of the meta tag!