I've already raised this issue once, but got no reply, so here goes again.
I'm using Contact Form 7 (1.9.5.1) on WordPress 2.7.1 with ReallySimpleCAPTCHA 1.0. I also have WPSuperCache on my site.
Every couple of days, I find the Captcha images disappear from my forms - I get a broken image-link in the browser. If I clear the cache in WPSuperCache and then re-load the pages containing the forms in my browser, the Captcha is now OK.
This is becoming a real nuisance, so does anybody know what might be happening here, and how I could fix it?
If not, I'll have to abandon CF7 and try using some other solution.