Is it possible to pull the newest thumbnail pics from a certain gallery category to the frontpage (above the forum) of IP.Board?

It is very possible.

And how is it possible?

This is probably better suited to IPSBeyond :)

There is at least one modification on there and another on Invision Modding

Although they are not limited to one category / album, they are a direct "mirror" of the existing random images part of the skin.

I have this on my board (link in profile if you want to see) and it works well :D

Because this would require modifications to IPB, it's not possible within the Gallery software at this time (we don't modify any core IPB files for our components), however there are modifications available that can do this sort of thing. The random images one yellow_spider mentioned, as I understand it, can be slightly altered to pull the latest images instead.

Thank you yellow_spider. I tried the one on IPSBeyond but I didn't get it to work. Let's hope that the one on Invision Modding will work.
Which one did you install on your site? (By the way, I was surprised when I looked at your birthay date... not too far from mine ^^)

I used this one > http://www.invisionmodding.com/index.php?showtopic=14688

Its $20 USD though but well worth it imo :)

Thank you for the link. :)