the images that will be uploaded in the forum / dynamic directory, will have alt and description, that was mentioned.

I want to know if the sitemap will have an image sitemap too  that will be submitted to the search engines?

Also, the ratings that are provided on the products listed on the directory, do they support schema.org microformats for ratings?

When smf is updated, what about the mods?

will they still work or need to be replaced?

1. No, but it can be added quite easily, I can show you how.

2. No, there is no images sitemap as SMF does not provides a way to make it.

3. No, those ratings aren't schema.org ready.

4. If it's a minor update (from SMF 2.0.9 -> 2.0.11) they will keep working as expected, if it's a major upgrade 2.0 to 2.1 I'd submit a new version compatible with it, but the existing installation won't be compatible.