Css Image Rollover Using "visibility: Hidden"

Hello,

I've read a lot about using CSS to hide text or images (Matt Cutts blog etc.) and I have a couple of questions about this issue...

If you follow my website-link: http://www.galleryvandijk.com/tamara_aladin/collectie_ta3_a.html,
you'll see a text-link: "More info"

1) If you hover over this text-link, a white coloured image is shown with extra productinfo, using the "css visibility:hidden" technique. Is this technique safe when considering SERPs and SEO?

2) If you hover the text-link "More Info", you'll also see the title of the image with a pink background saying: "Tamara Aladin - Tuulikki vase". This title is not part of the image and is HTML-text which is not visible for the visitor untill hovered over "More Info". Again I used the "css visibility:hidden" technique. Is this technique in this particular situation safe when considering SERPs and SEO?

Thanks.