last 1: http://www.w3schools.com/tags/tag_figcaption.asp - would that be OK HTMP cap style to use?

OK. So whether I use wordpress or HTML style captions does not matter. My web developers had set up wordpress stye and I was advised HTML captions may be better. I will leave as is then. thx again. These have been very clear and quality answers

this is great answer and you back it up with experiences you have seen.

Question: should this be HTML captions or can it be written text in wordpress below image? What kind of text works best for SEO?

Example I have a page with a slideshow of 35 pictures. They are all unique pictures and relevant to the page, have unique alt text, though no captions or description surrounding the images. Page also has a lot of unique written content.

Question: is this large nr of pictures potentially overwhelming for search engines and they may think it is spammy and it would be a safer bet to only keep the top 10 pictures on such page?

I did review this great whiteboard Friday - http://moz.com/blog/image-seo-basics-whiteboard-friday - and I noticed this at very end: "The other part, and I see this happen a lot especially with bigger clients, is when you put lots and lots of images on one page, like an image gallery, those pages tend to be very hard to get indexed. The reason for that is there's not a lot unique textual content. A lot of times it's just overwhelming to users. It doesn't provide a lot of benefit in a search result."

My page has been indexed, but will ranking potentially be hurt and to play it safe I better reduce nr of pictures? I do understand the "do what is best for the user" scenario and that is what I am doing with a lot of amazing original pictures not found on any other website. However, with search engines we obviously have to consider how they operate as well.

Thank you

Gianluca,
Rand's whiteboard Friday a couple of weeks ago may help you: http://moz.com/blog/handling-duplicate-content-across-large-numbers-of-urls

Though the Whiteboard Friday is about duplicate content issues, 1 piece you can probably us from it is this: embed an iframe on page of the content to leave the content out of the index and the content will not be perceived to be part of the URL when using iframe. Add “noindex” in the HTML doc in the iframe to be 100% sure that search engines do not index it.